The PR_END_OF_FILE_ERROR occurs in Firefox whenever there is an unexpected failure in establishing a secure SSL/TLS handshake between Firefox and the target server. Simply put, Firefox ends its process of negotiation without reaching a viable cipher suite and a secure pathway. In essence, the browser is unable to initiate a secure encrypted connection, which is why the PR_END_OF_FILE_ERROR may occur despite having an ideal internet connection.
That is exactly why the PR_END_OF_FILE_ERROR is so baffling. A website may be accessible through Chrome or Edge but not through Firefox since the issue usually stems from Firefox-specific network issues, profile settings, proxy problems, and HTTPS scanning by security applications. The most recent support forums and articles about the error always highlight how VPNs, proxies, antivirus scans, corrupt Firefox profiles, and DNS-over-HTTPS are the most frequent causes of pr_end_of_file_error.
In the following article, we will look into what causes an SSL/TLS handshake error and how to fix it step by step.
Why Firefox Shows pr_end_of_file_error
This simply means that there is some kind of interruption in the secure connection during the handshake process.
Some common reasons include:
- Incompatibility of VPN or Proxy
- HTTPS scanning by antivirus or firewall
- Firefox profile corruption
- Special SSL/TLS or DNS configuration
- In some cases, Cipher mismatch at server side
It turns out that in case of the pr_end_of_file_error, Firefox is not suffering from any bugs but actually has problems with the connection route. Firefox is very particular regarding secure negotiation; hence any disturbance caused by local software/changes results in the error message.
The Fastest Fixes to Try First
In case the goal is to go for the most efficient solution possible, try these things first.
1. Turn off your VPN or proxy
According to the Mozilla support and forum users, the most common cause of PR_END_OF_FILE_ERROR is using the above services. When a VPN changes the route or adds its filters, it becomes impossible for Firefox to establish an SSL connection.
2. Pause antivirus HTTPS scanning
Many security packages check encrypted traffic. While that might sound good, in reality, the process intercepts the certificate chain and fails to establish a secure connection with Firefox, causing the error. In case your package allows you to turn off the scanning, HTTPS checking, or encryption protection, try to do it and see what happens.
Expert solution for enterprise AV setup: If it is not possible to disable HTTPS scanning, one can change settings in Firefox to make it trust the OS certificate store. Open Firefox, enter about:config into the URL bar, confirm the warning message that appears, then find security.enterprise_roots.enabled setting and enable it. It will make Firefox trust certificates from the OS, which is usually necessary in order to avoid the pr_end_of_file_error on HTTPS websites.
3. Test in a Private Window
Using a Private Window allows you to avoid extension conflicts and browser data. In case the site works normally in Private mode, the problem lies either with the extension or browser data, not the site.
Firefox Settings That Fix the Problem
In the case that quick fixes do not resolve the issue, move onto troubleshooting the problem from within the Firefox application.
Check proxy settings
Go to Settings > Network Settings and check Firefox’s network setup. If an old proxy setting still exists on your computer, change the option to “No proxy” or “Use system proxy settings”. Incorrect proxy settings are the most common cause of the pr_end_of_file_error handshake in Firefox.
Disable DNS over HTTPS temporarily
Go to Settings, followed by Privacy & Security, and make sure DNS over HTTPS is Off. According to some troubleshooting sources, DNS over HTTPS can lead to the pr_end_of_file_error in Firefox in certain network situations, especially when there are security filtering systems operating on the network. Disable DNS over HTTPS and check if the problem gets resolved.
Reset Firefox or create a new Firefox profile
Firefox profile corruption is one of the most common reasons for a pr_end_of_file_error. This error may occur if Firefox has got corrupt certificates or network settings or if you have some conflicting extensions installed.
Also Read: How to Fix a 504 Gateway Time-Out (HTTP 504 Error Code)
What Typical Users Really Experience
The best advice from discussions on the matter of this problem is that pr_end_of_file_error vanishes right after just one local fix. At Mozilla’s discussion forums, the very first advice to get rid of the problem is to turn off all your VPN tools. Likewise, at Linux Mint community forums, the problem turns out to be the result of some interference from antivirus programs, proxy servers, and/or a VPN.
That is crucial for understanding the true nature of pr_end_of_file_error. It almost never means that the site you are visiting is hacked and potentially harmful to your system. In fact, pr_end_of_file_error almost always means that Firefox fails to perform the handshake due to some interference from your side.
Practical Example
Think about a situation when you enter an online bank site via Firefox and see pr_end_of_file_error immediately. However, that same site works perfectly fine via another browser. When you turn off your VPN, refresh the site, and try again, you succeed. That is a textbook example of pr_end_of_file_error firefox being not related to any external factors.
Yet another frequent situation is a work laptop with an aggressive antivirus that constantly scans encrypted traffic. Firefox starts displaying pr_end_of_file_error on many HTTPS sites. After you stop traffic inspection, everything works fine.
When the Website Itself Is the Problem
When you experience pr_end_of_file_error on one website, even when you have disabled the use of your firewall, proxy servers, and SSL/HTTPS scanning, the problem may be in the SSL configuration of the website. According to technical descriptions of the pr_end_of_file_error, Firefox may be able to get to the end of the cipher negotiation without having a common cipher. This means that there is a problem on the server side.
Try visiting the website using another computer. If you still experience the error in Firefox, contact the website administrator regarding the SSL error.
Conclusion
The pr_end_of_file_error is very annoying, but it is usually something that can be solved once you learn not to treat it like a mystery and start looking into it as a secure connection issue. The latest discussions on support forums list possible local solutions such as VPN use, proxy server, antivirus scanning of HTTPS requests, Firefox profile issue, and SSL/DNS issues. Do things in a step-by-step way: first of all, you need to turn off the use of your VPN, HTTPS scanning, the security.enterprise_roots.enabled parameter in about:config, and disable DNS over HTTPS in the Settings>Privacy & Security>DNS over HTTPS>Off settings. It’s most likely that these simple steps will solve your problem.
FAQs
What does the pr_end_of_file_error in Firefox stand for?
It is an error message which appears during SSL/TLS secure connection in the Firefox browser.
What does the term pr_end_of_file_error mean?
In simple words, it means that Firefox got to the end of the secure connection attempt but failed to establish it properly.
Why pr_end_of_file_error occurs in Firefox but not in other browsers?
The thing is that pr_end_of_file_error can be connected to some settings of Firefox itself, or proxy/DNS issues and Firefox profile corruption in some cases.
How do I fix the PR_END_OF_FILE_ERROR quickly?
Disable VPN, proxy, and HTTPS scanning in your antivirus software, and try connecting in a private window or refreshing Firefox profile.
Is there any chance that pr_end_of_file_error is caused by bad website certificate?
Yes, if the SSL/TLS and/or ciphers on the server side are badly configured.
