A particularly confusing Internet problem occurs when your computer appears to have a perfectly working connection, Google or YouTube opens normally, and perhaps email also works, but certain websites refuse to load.

You may experience situations such as:

• Google opens, but a business website does not.
• YouTube works, but a banking or government portal fails.
• A website works on your phone but not on your PC.
• The website works through mobile data but not through office Wi-Fi.
• One browser opens the website while another browser cannot.
• The website works in Incognito/InPrivate mode but not in normal browsing.
• Some websites continuously display Connecting, Loading, or This site can't be reached.
• The website opens after connecting to a VPN but fails through the normal Internet connection.

These symptoms usually mean that your Internet connection itself is not completely down. Instead, something is preventing your computer, browser, router, DNS server, ISP, security software, or network configuration from reaching specific destinations.

This guide explains how to systematically diagnose and fix the problem.

1. Common Error Messages

Depending on the underlying cause, Chrome, Microsoft Edge, Firefox, or another browser may display errors such as:

ERR_CONNECTION_TIMED_OUT

The browser attempted to connect to the server but did not receive a response within the expected period.

ERR_CONNECTION_RESET

The connection was unexpectedly terminated or reset.

ERR_NAME_NOT_RESOLVED

The domain name could not be translated into an IP address.

DNS_PROBE_FINISHED_NXDOMAIN

DNS could not locate the requested domain.

ERR_ADDRESS_UNREACHABLE

The destination address cannot currently be reached through the available network path.

ERR_SSL_PROTOCOL_ERROR

A problem occurred while establishing the secure HTTPS/TLS connection.

This site can't be reached

This is a general browser message that can be caused by DNS, routing, firewall, proxy, server, or connectivity problems.

Understanding the exact error displayed by the browser can considerably reduce troubleshooting time.

2. First Determine Whether the Website Is Actually Down

Before changing Windows settings, determine whether the problem belongs to your computer or the website itself.

Try opening several unrelated websites.

For example:

• Google
• Microsoft
• Wikipedia
• Your bank's website
• The problematic website

If almost everything works except one website, the problem may be on that website's side.

Possible causes include:

• Web server outage
• Hosting failure
• DNS configuration error
• Expired SSL certificate
• CDN outage
• Firewall configuration problem
• Database failure
• Website maintenance
• Geographic restrictions
• Your public IP being blocked

Try the same website from another Internet connection.

For example, disconnect your phone from Wi-Fi and access the website using mobile data.

If the website fails on multiple unrelated Internet connections and devices, there is a stronger possibility that the website itself is experiencing a problem.

3. Check Whether the Problem Affects One Device or All Devices

This is one of the most useful diagnostic tests.

Suppose:

PC: Website does not open
Phone on same Wi-Fi: Website opens

The problem is probably associated with the PC.

Possible causes include:

• Browser configuration
• Windows DNS cache
• Proxy settings
• Antivirus
• Firewall
• Hosts file
• Network adapter configuration
• Malware
• VPN software

Now consider:

PC: Website does not open
Phone on Wi-Fi: Website does not open
Phone using mobile data: Website opens

This points more strongly toward:

• Router
• ISP
• Router DNS
• Public IP blocking
• ISP routing
• Network-level filtering

This simple comparison can save considerable troubleshooting time.

4. Try Another Browser

Open the same website using another browser.

For example, if it fails in Chrome, try:

• Microsoft Edge
• Mozilla Firefox

If the website works in another browser, your Internet connection and Windows networking are probably functioning.

The problem is more likely related to the original browser.

Possible causes include:

• Corrupted browser cache
• Cookies
• Browser extensions
• Secure DNS configuration
• Proxy extension
• Security extension
• Corrupted browser profile

5. Test the Website in Incognito or InPrivate Mode

In Chrome, press:

Ctrl + Shift + N

In Microsoft Edge:

Ctrl + Shift + N

Then open the problematic website.

If the website works in private browsing but fails in normal browsing, investigate:

• Extensions
• Cookies
• Cached website files
• Browser profile settings

Disable extensions individually until the problematic extension is identified.

Common offenders include:

• Ad blockers
• VPN extensions
• Privacy extensions
• Script blockers
• Antivirus browser extensions
• Proxy extensions
• DNS/security extensions

6. Clear Browser Cache and Cookies

Corrupted cached content can occasionally prevent specific websites from loading correctly.

In Chrome or Edge, press:

Ctrl + Shift + Delete

Select the appropriate time range and clear cached images/files.

If necessary, clear cookies for the affected website as well.

Important: Clearing cookies can sign you out of websites.

Therefore, if the problem affects only one website, consider deleting that site's cookies instead of removing all browser cookies.

7. Check DNS Resolution

DNS converts a domain such as:

example.com

into an IP address that computers use to communicate.

DNS problems are among the most common reasons why some websites work while others do not.

Open Command Prompt and run:

nslookup example.com

Replace example.com with the problematic domain.

If DNS is functioning, you should normally receive one or more IP addresses.

If you receive errors such as:

Non-existent domain

or DNS requests time out, investigate DNS configuration.

8. Flush the Windows DNS Cache

Windows stores previously resolved DNS records locally.

A stale or corrupted DNS entry can sometimes prevent access to a website even though the website itself is functioning.

Open Command Prompt as Administrator and run:

ipconfig /flushdns

You should see:

Successfully flushed the DNS Resolver Cache.

Close and reopen the browser and test the website again.

9. Register DNS Again

You can also run:

ipconfig /registerdns

This refreshes DNS registration information for the computer.

It is particularly relevant in business networks using internal DNS or Active Directory environments.

10. Change the DNS Server

If your ISP's DNS server is having difficulty resolving certain domains, temporarily test a public DNS provider.

Google Public DNS

Preferred DNS: 8.8.8.8
Alternate DNS: 8.8.4.4

Cloudflare DNS

Preferred DNS: 1.1.1.1
Alternate DNS: 1.0.0.1

Quad9

Preferred DNS: 9.9.9.9
Alternate DNS: 149.112.112.112

After changing DNS, run:

ipconfig /flushdns

Then test the website again.

If the website immediately starts working, your previous DNS resolver may have been responsible.

11. Check Browser Secure DNS / DNS over HTTPS

Modern browsers can use their own secure DNS mechanism.

Therefore, changing Windows DNS may not always affect browser DNS requests.

In Chrome, review:

Settings → Privacy and security → Security → Use secure DNS

In Microsoft Edge, review the corresponding security/privacy settings for secure DNS.

For troubleshooting, test both configurations:

• Secure DNS enabled
• Secure DNS disabled

If changing this option resolves the issue, investigate the selected DNS provider or network policy.

12. Reset Winsock

Winsock controls how Windows applications interact with network services.

A damaged Winsock catalog can cause unusual Internet problems.

Open Command Prompt as Administrator and run:

netsh winsock reset

Restart the computer afterward.

13. Reset TCP/IP

If the problem persists, reset the Windows TCP/IP stack.

Run Command Prompt as Administrator:

netsh int ip reset

Then restart Windows.

You can combine several common repairs:

ipconfig /flushdns
netsh winsock reset
netsh int ip reset

Restart the computer after completing the commands.

Note: Network resets may affect manually configured network settings. Record static IP, gateway, and DNS settings before making changes on business computers or servers.

14. Renew the IP Address

For computers receiving their configuration through DHCP, try:

ipconfig /release
ipconfig /renew

Do not use this blindly on remotely accessed systems or computers with manually configured static addresses.

15. Check Proxy Settings

An incorrectly configured proxy can allow some destinations while preventing others.

In Windows 11, check:

Settings → Network & internet → Proxy

Unless your organization intentionally uses a proxy server, verify that an unexpected manual proxy has not been enabled.

You can also check:

Control Panel → Internet Options → Connections → LAN settings

Look for unauthorized proxy configuration.

Corporate environments may intentionally configure proxies through Group Policy, so consult the network administrator before changing managed settings.

16. Check for a VPN

VPN software changes the route Internet traffic takes.

Disconnect the VPN temporarily and test the website.

Also perform the reverse test:

If the website normally fails, connect through a trusted VPN and test it.

If:

Normal Internet → Website fails
VPN → Website works

the problem may involve:

• ISP routing
• Public IP blocking
• Geographic restrictions
• DNS filtering
• Network routing
• ISP filtering

A VPN working is a useful diagnostic clue, but it does not automatically mean a VPN should be used as the permanent solution.

17. Check the Windows Hosts File

Windows can manually map domain names through the Hosts file.

Its normal location is:

C:\Windows\System32\drivers\etc\hosts

Open Notepad as Administrator and inspect the file.

Suspicious entries may look like:

127.0.0.1 example.com
0.0.0.0 example.com

Such an entry can intentionally or accidentally block the website.

Do not remove legitimate corporate, development, testing, or application-specific entries unless you understand their purpose.

18. Check Antivirus and Endpoint Security

Security software may block websites because of:

• Web reputation
• Malicious URL detection
• HTTPS inspection
• Web filtering
• Parental controls
• DNS protection
• Content filtering
• SSL scanning

Check the security application's logs or notifications.

For diagnosis, use the product's documented temporary web-protection test if appropriate rather than permanently disabling antivirus protection.

If disabling a specific web-filtering component makes the website work, investigate why the site is being blocked before creating a permanent exclusion.

19. Check Windows Defender Firewall

Firewall rules can interfere with browsers or network connections.

Open:

Windows Security → Firewall & network protection

Review firewall configuration and any third-party firewall software.

For advanced inspection, run:

wf.msc

This opens Windows Defender Firewall with Advanced Security.

Check for unusual outbound rules affecting:

• Chrome
• Edge
• Firefox
• Ports 80 or 443
• Specific IP addresses
• Network profiles

Avoid disabling the firewall permanently merely to make a website work.

20. Test the Domain with Ping

Run:

ping example.com

There are several possible outcomes.

Domain resolves and replies

Example:

Reply from 93.x.x.x

DNS resolution and basic IP connectivity are working.

Domain resolves but ping times out

This does not necessarily mean the website is down.

Many web servers and firewalls intentionally block ICMP/ping requests.

Domain does not resolve

This suggests a DNS-related issue.

21. Run Tracert

Use:

tracert example.com

This shows the network path toward the destination.

If the route repeatedly fails at a particular point, there may be:

• ISP routing problems
• Upstream network issues
• Destination filtering
• Firewall restrictions

However, some routers intentionally do not respond to traceroute packets, so * * * entries alone do not prove a failure.

22. Test HTTPS Port 443

Most modern websites use HTTPS over TCP port 443.

PowerShell can test whether the destination port is reachable:

Test-NetConnection example.com -Port 443

Look for:

TcpTestSucceeded : True

If DNS resolves correctly but TCP port 443 consistently fails, investigate:

• Firewall
• Proxy
• ISP routing
• Destination firewall
• Security software
• Server availability

For HTTP websites, you can similarly test:

Test-NetConnection example.com -Port 80

23. Check System Date and Time

Incorrect date or time settings can cause HTTPS certificate validation failures.

Verify:

Settings → Time & language → Date & time

Check:

• Correct date
• Correct time
• Correct time zone
• Automatic time synchronization

This is especially important when browsers display certificate or SSL warnings.

24. Restart the Router

Restarting the router can clear temporary:

• DNS issues
• NAT table problems
• Routing problems
• Connection state problems
• Firmware glitches

Turn the router off, wait briefly, and start it again.

Do not factory-reset the router as an initial troubleshooting step.

A factory reset can erase:

• ISP credentials
• Static routes
• Port forwarding
• VPN configuration
• Wi-Fi settings
• Firewall rules

25. Test Using a Mobile Hotspot

This is one of the most powerful troubleshooting methods.

Disconnect the computer from the existing network and connect it to a mobile hotspot.

Then open the problematic website.

Website works through hotspot

The PC and browser are probably capable of reaching the website.

Investigate:

• Router
• ISP
• DNS
• Public IP blocking
• Network firewall
• Office filtering

Website still fails through hotspot

Investigate:

• Windows
• Browser
• Antivirus
• Proxy
• Hosts file
• Local firewall
• Browser extensions

This test quickly separates PC problems from network problems.

26. Check Whether Your Public IP Is Blocked

Websites sometimes block IP addresses because of:

• Too many requests
• Security rules
• Failed login attempts
• Bot detection
• Abuse detection
• Reputation systems
• Geographic restrictions
• Firewall rules

A typical clue is:

Home/Office Internet → Website fails
Mobile data → Website works
VPN → Website works

If this pattern occurs, contact the website administrator or your ISP before making unnecessary changes to Windows.

27. Check IPv4 and IPv6

Some connectivity problems occur when IPv6 is configured incorrectly by the router or ISP.

A domain may have both:

A record = IPv4
AAAA record = IPv6

If IPv6 connectivity is broken, some connections may behave inconsistently.

You can examine DNS records using:

nslookup example.com

and perform additional IPv4/IPv6 testing where appropriate.

Temporarily changing IPv6 settings can be useful diagnostically, but permanently disabling IPv6 should not be the default solution because modern Windows and many networks are designed to support it.

28. Consider an MTU Problem

MTU stands for Maximum Transmission Unit.

An incorrect MTU can create unusual symptoms where:

• Small websites work.
• Some HTTPS websites fail.
• Login pages hang.
• Certain pages partially load.
• VPN connections behave differently.

MTU problems are particularly relevant with:

• PPPoE
• VPNs
• Tunnels
• Certain ISP connections
• Complex router configurations

MTU should normally be investigated only after more common DNS, browser, firewall, and routing causes have been eliminated.

29. Reset the Network Adapter

Windows 11 provides a network reset option.

Go to:

Settings → Network & internet → Advanced network settings → Network reset

This reinstalls network adapters and resets many networking components.

Use this as a later troubleshooting step rather than the first one.

You may need to reconfigure:

• Wi-Fi networks
• VPN adapters
• Virtual network adapters
• Static IP configuration
• Custom DNS settings

30. Check for Malware or Unwanted Software

Malware, adware, browser hijackers, and unwanted applications can manipulate:

• DNS
• Proxy settings
• Hosts file
• Browser extensions
• Certificates
• Network traffic

Run a complete security scan using a reputable and updated security product.

Also inspect:

Settings → Apps → Installed apps

Look for recently installed or unfamiliar applications.

Check browser extensions carefully as well.

31. Website Works on Phone but Not PC

If the phone and PC are using the same Wi-Fi, but only the PC fails, prioritize:

1. Another browser
2. Incognito/InPrivate mode
3. Browser cache
4. Browser extensions
5. Windows DNS cache
6. Proxy
7. Hosts file
8. Antivirus
9. Firewall
10. Winsock/TCP-IP

This strongly suggests a local computer problem rather than an ISP-wide outage.

32. Website Works on Mobile Data but Not Wi-Fi

If the website works through mobile data but fails when the same phone uses Wi-Fi, investigate:

• Router DNS
• ISP DNS
• ISP routing
• Router firewall
• Parental controls
• DNS filtering
• Public IP blocking
• Office firewall
• Network content filtering

Changing Windows browser settings will not necessarily solve a network-level problem.

33. Website Works in One Browser but Not Another

This normally points toward a browser-specific issue.

Check:

• Extensions
• Cache
• Cookies
• Secure DNS
• Proxy extensions
• Browser profile
• Browser security settings

Resetting or reinstalling the browser should generally be considered only after these simpler checks.

34. Website Works with VPN but Not Without VPN

This is an important diagnostic pattern.

Possible explanations include:

• ISP routing problem
• DNS filtering
• Geographic restriction
• Website blocking your public IP
• Network filtering
• Upstream routing problem

Because a VPN changes your route, DNS behavior, and public IP address, successful access through a VPN can help narrow the investigation.

35. Website Works by IP Address but Not by Domain Name

If a service is reachable by IP address but not by domain name, DNS should be investigated first.

Check:

nslookup example.com

Then:

ipconfig /flushdns

Try a different DNS resolver.

Also inspect:

C:\Windows\System32\drivers\etc\hosts

This pattern is a strong indication of a name-resolution problem.

36. Website Resolves but HTTPS Still Fails

Suppose:

nslookup example.com

successfully returns an IP address, but the website still does not open.

DNS may therefore be functioning correctly.

Next test:

Test-NetConnection example.com -Port 443

If TCP port 443 succeeds but the browser displays an SSL error, investigate:

• System date/time
• TLS compatibility
• Browser
• Antivirus HTTPS scanning
• Proxy inspection
• Certificate problems
• Website SSL configuration

37. Recommended Diagnostic Command Set

For advanced troubleshooting, the following commands provide useful information.

View complete IP configuration

ipconfig /all

Flush DNS

ipconfig /flushdns

Test DNS

nslookup example.com

Test basic reachability

ping example.com

Trace route

tracert example.com

Test HTTPS

Test-NetConnection example.com -Port 443

Reset Winsock

netsh winsock reset

Reset TCP/IP

netsh int ip reset

Restart Windows after performing network-stack resets.

38. A Fast Troubleshooting Flow

A practical troubleshooting sequence is:

Step 1: Confirm other websites work.

Step 2: Test the problematic website on another device.

Step 3: Test using mobile data/mobile hotspot.

Step 4: Try another browser.

Step 5: Try Incognito/InPrivate mode.

Step 6: Run:

nslookup example.com

Step 7: Flush DNS:

ipconfig /flushdns

Step 8: Try a different DNS provider.

Step 9: Check proxy and VPN settings.

Step 10: Check the Hosts file.

Step 11: Check antivirus/web protection.

Step 12: Check firewall rules.

Step 13: Run:

tracert example.com

Step 14: Test:

Test-NetConnection example.com -Port 443

Step 15: Reset Winsock/TCP-IP if the evidence points toward a local Windows networking problem.

This sequence avoids unnecessary destructive changes.

39. Quick Symptom-to-Cause Reference

Symptom	Most Likely Area to Investigate
All websites fail	Internet/router/network adapter
Only one website fails	Website/server/DNS/IP blocking
Several unrelated sites fail	DNS/routing/security filtering
Works on phone and PC uses same Wi-Fi	PC/browser/security configuration
Works on mobile data but not Wi-Fi	Router/ISP/DNS/public IP
Works in another browser	Browser configuration
Works in Incognito mode	Extensions/cookies/cache
Works with VPN	ISP routing/DNS/public IP/geographic filtering
Works after changing DNS	Previous DNS resolver
Domain does not resolve	DNS
Domain resolves but port 443 fails	Routing/firewall/server/security software
HTTPS certificate warning	Date/time/TLS/certificate/security inspection
Random websites partially load	DNS/MTU/IPv6/proxy/security filtering

40. What You Should Not Do Immediately

Avoid jumping directly to drastic actions such as:

• Formatting Windows
• Reinstalling Windows
• Factory-resetting the router
• Permanently disabling antivirus
• Permanently disabling the firewall
• Deleting unknown certificates
• Randomly modifying Registry settings
• Permanently disabling IPv6
• Installing multiple "Internet repair" utilities

Selective website-access problems are usually diagnosable without reinstalling Windows.

FAQ

1. Why do some websites open while others don't?

Common causes include DNS problems, browser cache, extensions, proxy settings, VPN configuration, firewall rules, antivirus filtering, router problems, ISP routing, IPv6 issues, or the website itself being unavailable.

2. Can DNS cause only some websites to stop working?

Yes. DNS problems can affect specific domains while other previously cached or correctly resolved domains continue working.

3. Which command clears the DNS cache in Windows?

Use:

ipconfig /flushdns

4. Which DNS server can I test?

Common options include Google Public DNS (8.8.8.8), Cloudflare (1.1.1.1), and Quad9 (9.9.9.9).

5. Why does a website work on my phone but not my computer?

If both devices use the same Wi-Fi, the computer may have a browser, DNS cache, proxy, firewall, antivirus, Hosts file, or network-stack problem.

6. Why does a website work on mobile data but not Wi-Fi?

The problem may involve the router, ISP, DNS server, public IP address, firewall, or network-level filtering.

7. Why does the website work in Incognito mode?

An extension, cookie, cached file, or browser-profile setting may be causing the problem.

8. Why does changing DNS fix websites?

Your previous DNS resolver may have had stale, incorrect, filtered, or unavailable records for the domain.

9. Does a failed ping mean the website is down?

No. Many servers intentionally block ICMP/ping while allowing normal HTTPS traffic.

10. How can I check whether HTTPS is reachable?

Use PowerShell:

Test-NetConnection example.com -Port 443

11. Why does the website open when I use a VPN?

The VPN changes your public IP and network route and may also change DNS resolution. This can bypass an ISP routing issue, DNS problem, geographic restriction, or public-IP block.

12. Can antivirus block only one website?

Yes. Modern security software can block individual URLs or domains based on reputation, malware detection, category filtering, or HTTPS inspection.

13. Can Windows Firewall block certain websites?

It can indirectly prevent access through rules affecting applications, protocols, ports, or destination addresses.

14. Can the Hosts file block a website?

Yes. An entry mapping a domain to 127.0.0.1, 0.0.0.0, or another incorrect IP can prevent normal access.

15. Where is the Windows Hosts file?

It is normally located at:

C:\Windows\System32\drivers\etc\hosts

16. Can incorrect date and time stop websites from opening?

Yes. Incorrect system time can cause HTTPS certificate validation errors.

17. Should I disable IPv6?

Not as a normal permanent fix. Temporarily testing IPv6 behavior can help diagnose certain network problems, but IPv6 should generally remain enabled unless a specific configuration problem has been identified.

18. What does ERR_NAME_NOT_RESOLVED mean?

It generally indicates that the browser could not resolve the website's hostname through DNS.

19. What does ERR_CONNECTION_TIMED_OUT mean?

The browser attempted to establish a connection but did not receive the expected response before the timeout.

20. What does ERR_CONNECTION_RESET mean?

It means an established or attempted connection was unexpectedly reset by a device, server, security system, or network component.

21. Can the router cause only certain websites to fail?

Yes. Router DNS, firewall rules, parental controls, MTU settings, IPv6 configuration, firmware problems, and filtering can selectively affect websites.

22. Should I reset my router?

Restarting the router is reasonable. A factory reset should generally be a later step because it can erase ISP and network configuration.

23. Should I reinstall Windows?

Usually not. This problem should first be isolated using browser, device, DNS, hotspot, proxy, firewall, and network tests.

24. What is the fastest way to determine whether the PC or Internet connection is responsible?

Connect the PC to a mobile hotspot.

If the website works through the hotspot, investigate the normal router/ISP/network. If it still fails, investigate the PC.

25. What is the best troubleshooting approach?

Do not randomly change settings. Determine whether the failure follows the website, browser, computer, Wi-Fi network, ISP connection, or public IP address. Once the problem is isolated to one layer, the correct solution becomes much easier to identify.

Conclusion

When some websites open normally but others do not, the Internet connection is rarely completely broken. The problem is usually limited to a specific layer such as DNS resolution, browser configuration, proxy/VPN settings, security filtering, Windows networking, router configuration, ISP routing, or the destination website.

The most effective diagnostic technique is comparison:

Another website
        ↓
Another browser
        ↓
Incognito/InPrivate
        ↓
Another device
        ↓
Mobile hotspot
        ↓
DNS test
        ↓
Port 443 test
        ↓
Router/ISP investigation

These comparisons help answer the most important question:

Is the problem with the website, browser, computer, local network, ISP, or destination server?

Once that is established, troubleshooting becomes significantly faster and avoids unnecessary actions such as reinstalling Windows or factory-resetting the router.

#Tags

#SomeWebsitesNotOpening #WebsiteNotLoading #InternetTroubleshooting #Windows11 #Windows10 #NetworkTroubleshooting #DNSTroubleshooting #DNSProblem #FlushDNS #ChangeDNS #GoogleDNS #CloudflareDNS #Quad9DNS #ChromeTroubleshooting #EdgeTroubleshooting #FirefoxTroubleshooting #BrowserProblem #InternetProblem #WebsiteConnectionError #ConnectionTimedOut #ConnectionReset #DNSProbeFinishedNXDomain #NameNotResolved #WinsockReset #TCPIPReset #NetworkReset #WindowsNetworking #ProxyProblem #VPNProblem #FirewallProblem #AntivirusBlocking #WebsiteBlocked #HostsFile #SSLProblem #HTTPSProblem #IPv6 #IPv4 #MTU #RouterTroubleshooting #ISPIssue #NetworkSecurity #WebFiltering #TestNetConnection #Nslookup #Tracert #PingTest #Port443 #SecureDNS #DNSOverHTTPS #TechnicalSupport