Problem PR_CONNECT_RESET_ ERROR Occurs when a user tries to use Mozilla Firefox to connect to a web server with HTTPS protocol, but the request is denied, which means that the counterpart or middle box (most likely the firewall) is forcing the connection Hangs up.


As it turns out, TCP protocol filtering can be responsible for disconnecting the end user (you) and the web server that you have access to because of false positives, and you should be able to fix the problem by accessing your advanced AV settings and disabling the protocol filter. ESET AV has enabled this feature by default. This problem may also be caused by some temporary files, which usually happens if the user tries to access the same website with a normal connection and a filtered VPN / Proxy. In this case, you can clear the problem by clearing your browser cache. An overprotective firewall can also be responsible for the interruption between the end user and the web server. False positives can be responsible for this behavior. If this scenario works, you can fix the problem reverting to the default Windows firewall.

Some websites take security for those who filter their connection via VPN or proxy. You may encounter this problem due to using a VPN or proxy. In this case, you can fix the problem by disabling the proxy server or deleting the VPN client. Depending on your ISP, you may also see this Firefox error due to a geolocation lock that prevents some web servers from accessing certain locations. In this case, you can change your location through the VPN tool to access the website. This problem is very common among users who try to access certain web servers from the university or workplace. Some restricted networks like this block users from accessing certain websites. The Brave browser is a good alternative.

1. Disable the protocol filter (if any)

As you can see, one of the most common reasons for this is called TCP filtering, which ultimately cuts the connection between the counterpart (you) and the server you are trying to access. In most cases, this is due to the AV protection set that has enabled the filtering protocol by default. This security feature ultimately checks the security of all your browser communications and blocks any suspicious activity. This is great when it works perfectly with advertising. But some AV (mostly ESET) are known to cause a lot of false positives that ultimately prevent users from accessing certain websites.

  • Open the main ESET antivirus program.
  • Access the advanced settings manually or by pressing F5.
  • Once you enter the advanced settings window, start by clicking on the web and email.
  • Next, expand the Protocol Filtering section and click on the corresponding slider next to Enable protocol application filter filtering to disable this feature.
  • Click Ok to save the changes, then see if the problem is resolved by trying to access the same website that previously caused the error.

Disable protocol filtering in ESET

Note: If you are using a different AV that uses protocol filtering, obviously the above steps will not apply. In this case, search the third-party AV you are using. If this operation did not work or you found that the ESET protocol filter did not cause PR_CONNECT_RESET_ERROR, go to the next possible fix below.

2. Clear the browser cache

As it turns out, this particular problem can also be caused by a temporary file that interferes with new communications. In most cases, this happens if you want to access the same web server with a normal connection and a VPN. You can probably fix the problem by clearing your Firefox web cache, if this scenario applies to your current situation. Here is a quick guide on how to do this to fix PR_CONNECT_RESET_ERROR:

Note: If you know exactly which file is causing the problem, here is how to clear the cache on a single website.

  1. Start by making sure all Firefox tabs are closed except for one new tab we’re going to use.
  2. Click the action button (top right corner of the screen) and select Options from the new popup menu.
  3. After entering the settings menu, select the Privacy & Security menu from the table on the left. Next, scroll down to C.