Firefox PR_END_OF_FILE_ERROR — Secure Connection Failed

Firefox PR_END_OF_FILE_ERROR indicates an SSL/TLS handshake failure where no common encryption protocol could be negotiated with the server. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: Error code: PR_END_OF_FILE_ERROR in Firefox's NSS library. The browser and server could not agree on a TLS version or cipher suite. Common when servers only support outdated TLS versions (1.0/1.1). Can also occur when security software intercepts HTTPS and presents incompatible ciphers. Firefox shows 'Secure Connection Failed' with this specific error code. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: Server only supports TLS 1.0 or 1.1 which Firefox has deprecated. Antivirus or firewall performing SSL inspection with incompatible ciphers. Firefox TLS settings modified to be too restrictive. Server certificate chain incomplete. Corporate proxy rejecting the connection during handshake. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Check if the site works in Chrome — if yes, it is a Firefox-specific TLS config issue. Temporarily disable antivirus SSL/HTTPS inspection. Check Firefox TLS settings: about:config > search security.tls.version.min (should be 3 for TLS 1.2). Reset Firefox TLS settings: about:config > search security.tls > reset all modified entries. If the server only supports TLS 1.0/1.1, contact the website admin to upgrade. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our Browser Errors collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.