How to Fix Firefox Losing Internet Connection: Step-by-Step Troubleshooting Guide

Mozilla Firefox is one of the most popular web browsers, but users occasionally experience connectivity problems that prevent websites from loading, even when their internet connection is working normally.

If Firefox keeps losing its internet connection while other browsers, such as Google Chrome or Microsoft Edge, continue working, the problem may be related to Firefox’s browser settings, cached data, DNS configuration, proxy settings, or installed extensions.

Fortunately, several troubleshooting methods can help restore Firefox’s internet connectivity without requiring users to reinstall the browser.

Here’s how to fix Firefox internet connection problems in 2026.

1. Clear Firefox Cache and Cookies

One of the easiest ways to resolve Firefox connectivity issues is to clear the browser’s cache and cookies.

Firefox stores temporary website files, cookies, and other browsing information to improve loading speeds. However, outdated or corrupted data can sometimes cause websites to load incorrectly or fail to connect.

How to Clear Firefox Cache and Cookies

1. Open Mozilla Firefox.
2. Click the three-line menu in the upper-right corner.
3. Select Settings.
4. Navigate to Privacy & Security.
5. Find the Cookies and Site Data section.
6. Click Clear Data or the corresponding clearing option in your Firefox version.
7. Select cached web content and, if necessary, cookies and site data.
8. Confirm the action.
9. Restart Firefox and test your internet connection.

Important: Clearing cookies may sign you out of websites and remove saved site preferences.

If Firefox continues losing its internet connection, proceed to the next troubleshooting method.

2. Disable DNS Over HTTPS in Firefox

DNS over HTTPS (DoH) is a privacy feature that encrypts DNS requests, helping prevent third parties from monitoring website lookups.

However, certain networks, DNS providers, firewalls, or security configurations may experience compatibility problems with this feature.

Disabling DNS over HTTPS temporarily can help determine whether it is responsible for Firefox’s connectivity problems.

How to Disable DNS Over HTTPS

1. Open Firefox.
2. Click the menu button and select Settings.
3. Navigate to Privacy & Security.
4. Scroll to the DNS over HTTPS section.
5. Select Off.
6. Restart Firefox.
7. Try opening a website.

If Firefox reconnects successfully, the DNS configuration may have contributed to the issue.

Keep in mind that disabling DNS over HTTPS changes how Firefox handles DNS privacy. Consider restoring the setting after troubleshooting or configuring a compatible DNS provider.

3. Check Firefox Proxy Settings

Incorrect proxy settings can prevent Firefox from accessing websites even when your computer is connected to the internet.

A proxy server acts as an intermediary between your browser and the internet. If Firefox is configured to use an unavailable or incorrectly configured proxy, connection errors may occur.

How to Check Firefox Proxy Settings

1. Open Firefox.
2. Navigate to Settings.
3. Select General.
4. Scroll down to Network Settings.
5. Click Settings.
6. Review the current proxy configuration.
7. If you do not require a proxy, try No proxy or Use system proxy settings, depending on your network.
8. Click OK.
9. Restart Firefox and test your connection.

Users connected to corporate networks, VPN services, or managed internet environments should verify their required proxy configuration before making permanent changes.

4. Start Firefox in Troubleshoot Mode

Firefox Troubleshoot Mode is a built-in diagnostic feature that temporarily disables extensions, themes, and certain hardware acceleration features.

This mode helps identify whether browser customizations are interfering with Firefox’s ability to connect to the internet.

How to Launch Firefox Troubleshoot Mode

1. Open Firefox.
2. Click the three-line menu.
3. Select Help.
4. Click Troubleshoot Mode.
5. Confirm that you want to restart Firefox.
6. Once Firefox reopens, test your internet connection.

If Firefox works correctly in Troubleshoot Mode, an extension, theme, or graphics-related setting may be contributing to the problem.

What to Do If Troubleshoot Mode Fixes Firefox

Return to normal Firefox mode and disable extensions individually.

After disabling each extension, test whether the browser maintains its internet connection.

Pay particular attention to VPN extensions, ad blockers, privacy tools, and security extensions that modify network requests.

5. Restart Firefox and Your Internet Connection

Sometimes, Firefox connectivity issues are caused by temporary network interruptions rather than browser settings.

Restarting the browser, computer, or networking equipment can resolve certain temporary connection problems.

Try the following:

• Close Firefox completely and reopen it.
• Restart your computer.
• Disconnect and reconnect to Wi-Fi.
• Restart your modem or router if appropriate.
• Test the same websites using another browser.

If every browser is experiencing connection problems, the issue may involve your internet service provider, router, operating system, or local network rather than Firefox itself.

6. Update Firefox to the Latest Version

Running an outdated Firefox version can expose users to bugs, compatibility issues, and security vulnerabilities.

Mozilla regularly releases Firefox updates that include security patches, stability improvements, and bug fixes.

How to Update Firefox

1. Open Firefox.
2. Click the menu button.
3. Select Help.
4. Click About Firefox.
5. Allow Firefox to check for available updates.
6. Install any available update.
7. Restart the browser when prompted.

After updating Firefox, check whether the internet connection remains stable.

7. Refresh Firefox If Connection Problems Continue

If previous troubleshooting methods fail, Firefox offers a Refresh feature that restores many browser settings to their default state while preserving important personal information.

Refreshing Firefox can remove extensions and reset customized settings that may be causing connectivity problems.

How to Refresh Firefox

1. Open Firefox.
2. Type about:support into the address bar.
3. Press Enter.
4. Locate Refresh Firefox.
5. Click the button.
6. Confirm the refresh.
7. Reopen Firefox and test your internet connection.

Note: Refreshing Firefox preserves information such as bookmarks and passwords but removes extensions and resets various settings. Consider backing up important browser data before proceeding.

Common Firefox Internet Connection Errors

Firefox users may encounter different error messages depending on the underlying issue.

Firefox Error	Possible Cause
Server Not Found	DNS resolution problems or incorrect website address
Unable to Connect	Server unavailable, blocked connection, or network issue
Secure Connection Failed	Certificate, TLS, or security software issue
Proxy Server Is Refusing Connections	Incorrect or unavailable proxy configuration
Connection Timed Out	Network interruption, firewall restrictions, or server delay

Identifying the specific error message can help determine which troubleshooting method to try first.

Frequently Asked Questions

Why does Firefox lose internet connection while Chrome works?

If Chrome connects normally but Firefox does not, the issue may involve Firefox-specific DNS settings, proxy configurations, extensions, or browser data. Testing Firefox in Troubleshoot Mode can help isolate the cause.

Does clearing Firefox cache fix internet problems?

Clearing Firefox’s cache can resolve problems caused by corrupted or outdated cached files. However, it may not fix issues related to DNS, proxy settings, firewalls, or internet service interruptions.

Should I disable DNS over HTTPS in Firefox?

Disabling DNS over HTTPS temporarily is a useful troubleshooting step when diagnosing DNS-related connectivity problems. However, it reduces DNS request encryption within Firefox, so users should consider re-enabling it once the problem is identified.

How do I reset Firefox without losing bookmarks?

Use the Firefox Refresh feature by opening about:support and selecting Refresh Firefox. The process generally preserves bookmarks, passwords, and browsing history while removing extensions and resetting certain settings.

Can Firefox extensions cause internet connection problems?

Yes. Certain VPN, privacy, security, and network-related extensions can interfere with website connectivity. Firefox Troubleshoot Mode temporarily disables extensions to help identify whether they are responsible.

Final Thoughts: How to Restore Firefox’s Internet Connection

If Mozilla Firefox keeps losing its internet connection, start with the simplest troubleshooting methods before resetting the browser.

Clearing cached data, checking DNS over HTTPS settings, reviewing proxy configurations, and launching Firefox in Troubleshoot Mode can help identify many common browser connectivity issues.

If these steps do not resolve the problem, updating Firefox, restarting networking equipment, or refreshing the browser may help.

For additional assistance, visit the official Mozilla Firefox Support website for troubleshooting instructions and community support.

Bottom line: Firefox internet connection problems do not always indicate that your internet service is down. In many cases, the issue may be isolated to browser settings, extensions, or local network configurations.