Firefox won’t run with VPN? Here’s how to fix it [8 methods]

by Aleksandar Ognjanovic

Troubleshooting Expert

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In the browser race, you’ll need to be original in order to par Chrome that’s still the leading solution. Mozilla made a lot of positive changes with speedy Quantum version, but it seems that there are some VPN-related problems that emerged thereafter. Certain users have had a hard time using Mozilla Firefox while VPN is enabled.

For that reason, we provided a few steps that should help you address this. In case none of the solutions help you, we advise you to send a ticket to your VPN provider. In the meanwhile, check the steps we provided below.

How can I fix common VPN issues in Mozilla Firefox?

1. Try Private Internet Access

Private Internet Access is the go-to VPN when you want to remain anonymous on the web. If your current Firefox VPN client has issues, maybe it’s time to switch to one that supports most major browsers and platforms. Additionally, PIA has a team of friendly support staff always there to help with any issues.

That being said, you’ll probably not need their assistance, as PIA has been thoroughly tested and there are no compatibility issues between it and with Mozilla Firefox.

By using PIA, you can encrypt your data to make sure it is unreadable in case it’s ever intercepted. Also, you can privately browse the web by installing the Firefox extension, or if you are on mobile, their dedicated private browser.

Moreover, you can set up your PIA client to always have certain apps work only in VPN mode. This can be easily done from the settings and it offers you per-app control over when you want to VPN to be active. This feature is something that most other VPN clients lack and it means that you set it up once and forget it.

Here are some other PIA features you might be interested in:

• 30-day money-back guarantee
• Protection for 10 devices at once
• Over 3300 servers in more than 45 countries
• SOCKS5 Proxy protocol
• Multiple VPN protocols, including WireGuard, PPTP, OpenVPN and L2TP/IPSec
• Military-grade encryption
• Support for Android, iOS, Windows, Mac and Linux
• Firefox, Opera and Chrome extensions

Private Internet Access

Private Internet Access will protect all your devices and browsers at the same time. Enjoy a major discount right away!

2. Check the connection settings

Before we move to a more internal approach to the problem, let’s make sure that the connection isn’t the one spoiling the Firefox experience. The first obvious step is to try an alternative browser in combination with your VPN and see for yourself. Additionally, if your Firefox VPN extension is having issues, try to remove it and add it again.

In case everything is working fine and the Firefox + VPN combo is malfunctioning, continue with the steps below. On the other hand, if you can confirm that the internet is completely off, follow these instructions to fix it:

1. Restart the PC.
2. Restart your router and/or modem.
3. Use a wired connection. It’s much more stable.
4. Check the network drivers. Navigate to Device Manager and check are they properly installed.
5. Run Windows Troubleshooter:
   1. Right-click Start and open Settings.
   2. Open Update & security.
   3. Select Troubleshoot from the left pane.
   4. Select Internet Connections and click on the ”Run the troubleshooter” button.
6. Reset IP address with Command Prompt:
   1. Type cmd in the Search bar, right-click on Command Prompt and run it as an administrator.
   2. In the command line, copy and paste the following lines one by one and press Enter after each:
      • netsh winsock reset
      • netsh int ip reset
      • ipconfig /release
      • ipconfig /renew

On the contrary, if everything is as intended and internet connection isn’t to be blamed for Firefox/VPN conundrums, continue with the steps below.

However, we would like to mention that, in most cases it’s not the browser to be blamed: VPN‘s compatibility can also be the problem.

3. Clear browser cache

No matter how much impacts the overall speed and decreases the page loading time, pilled up browser cache can cause a plethora of issues. That’s the good enough reason to clean it up and start from a scratch. We can’t say with certainty is it or is not causing the issues with VPN, but it’s one of those common troubleshooting steps.

If you’re not sure how to clear cache in Mozilla Firefox, make sure to follow the steps below:

1. Open Firefox.
2. Press Ctrl + Shift + Delete to access the Clear recent history dialog box.
3. Under the Time range to clear drop-down menu, select Everything.
4. Make sure to check the Cache box. It’s up to you whether you want to delete the rest or not.
5. Click on Clear Now.

If you’re still looking at the same blank screen, take a look at the next step.

4. Update Mozilla and VPN

Mozilla decided to take their game to another level and changed a lot of things with the introduction of Firefox Quantum. However, not all VPN solutions (the ones with browser extensions) support Firefox Quantum.

Furthermore, while you’re reading these lines, their respective developers are probably working on optimization for the brand new browsing solution. Therefore, make sure that both your VPN and Firefox are up to date.

Mozilla Firefox gets updated automatically, and that’s also the case for any browser extensions you have active, but you should double-check that everything is up to date if your Firefox VPN is having problems  If you’re unaware of how to update Mozilla Firefox, these steps should provide a proper insight:

1. Open Mozilla Firefox
2. Click on the burger menu and click on Help
3. Click on About Firefox
4. If it’s not up to date, the system will update Firefox to it’s latest version

Also, you can try and run Firefox in Safe mode, without add-ons included. Here’s how to do it:

1. Open Firefox.
2. Click on the burger menu and then on Help.
3. Click on Restart with Add-ons disabled

5. Inspect antivirus and firewall

Antivirus solutions that come with the dedicated firewalls can quite a good addition to security. On the other hand, some of those are remarkably strict and known for blocking apps that should be of the leash by default. That’s the job done overzealously. What you can do to overcome that wall (no pun intended) is to either disable the firewall temporarily (or permanently if you’re satisfied with Windows Firewall) or to whitelist the VPN and Firefox.

In addition, on the rarest occasions (and especially after the security updates), Windows Firewall can behave in the same manner as a third-party firewall. Even though the majority of VPN solutions are by default allowed to communicate through the Windows-native firewall, there’s always an exception.

If you’re not sure how to create an exception in the Windows Firewall, just follow the steps below:

1. Type Firewall in the search bar and select Allow an app through Windows Firewall
2. Click Change settings
3. Select Allow another app
4. Navigate to VPNs EXE file
5. Click Add
6. Allow the VPN to communicate through Public and Private networks.
7. Click OK to confirm changes.

6. Switch VPN servers

Making the best of your VPN requires stable servers with various locations. The best-case scenario is when they come in numbers, so you can choose the most fitting one. Occasionally you’ll have to switch between servers, especially if they are down or too slow.

The farther the server is, the bigger the latency and slower connection. However, there’s also, as we mentioned, the possibility of servers crashing or temporal unavailability.

In other words, there’s a chance that the faulty server is working against you. Therefore, make sure to try various servers and give it another go.

In addition, it’s only a side note, but you can try to change the encryption protocols and look for changes.

7. Remove Adware

The dangers of Adware infections and browser hijackers are quite present nowadays. In the best-case scenario, you can expect the bundle of pop-ups or your default search engine being changed. In the worst-case scenario, you’ll be looking at browser malfunctioning and more serious malware spreading all over your system.

We’re always for the better safe than sorry approach when it comes to dealing with malware, so it’s highly advised to use a specified third-party tool and scan your PC.

There’s a large variety of antivirus solutions that offer browser protection and Adware removal, but in our honest opinion, nothing does the better job then Malwarebytes AdwCleaner for Adware and PUPs (Potentially Unwanted Programs).

Below are the instructions on how to download and use this nifty tool:

1. Download Malwarebytes AdwCleaner, here
2. Run the application and click on Scan.
3. Remove everything even mildly suspicious and restart your PC.
4. Try running Mozilla Firefox again.

Foxiebro malware: How it works and how to remove it

8. Clean reinstall Mozilla Firefox

Finally, if none of the previous solutions helped you address the problem with Firefox and VPN, you can always clean reinstall Mozilla and VPN. The latter shouldn’t change much, but a lot of users found Firefox reinstallation as the cure for the ache. If you’re not sure how to perform a clean reinstallation of Mozilla Firefox, these steps should help you substantially:

1. Close Firefox.
2. In the Windows Search bar, type Control and open Control Panel.
3. In the Category view, select Uninstall a program.
4. Uninstall Firefox.
5. Navigate to these locations and delete Mozilla Firefox and Mozilla folders respectively:
   • C: > Program Files > Mozilla Firefox or C: > Program Files (x86) > Mozilla Firefox
   • C: > Users > Your Username > AppData > Local > Mozilla
6. Download the latest available Firefox version, here.

That should conclude it. In case you have any alternative solutions or questions regarding the solutions we offered, don’t hesitate to post them below. The comments section is just a few scrolls down.

FAQ: Firefox VPN issues

• How do I enable VPN on Firefox?

If you have a desktop VPN client, it will work independently of Firefox. You can connect to a server before you fire-up the browser. If you opt to go for the browser extension VPN, then you should be able to see if it’s active from the icon.

• Does Firefox have built in VPN?

By default, no. Firefox does not ship with a VPN, however, Mozilla has its own VPN which is currently only available in the US. That being said, you can download a VPN browser extension like the one offered by PIA and use it with Firefox.

No. Firefox Private Network is only available in the US and it not free.

Editor’s Note: This article was originally published in December 2017 and was revamped and updated in February 2021 for freshness, accuracy, and comprehensiveness.