Performance and connectivity Deal with error messages, crashing applications, connectivity issues, and slow performance. ஆங்கிலத்தில் Server Not Found - Troubleshoot connection problems Fix "The bookmarks and history system will not be functional" error message Secure connection and security warning error pages in Firefox Captive portal detection Fix error “Website will not allow Firefox to display the page.” Troubleshoot time-related errors on secure websites Crash reports in Firefox for Android Troubleshoot Mode Thunderbird How can I tell if Mozilla VPN is connected? Firefox can't load websites but other browsers can Fix Firefox using too much memory or CPU resources Connection settings in Firefox Resist Fingerprinting Use Troubleshoot Mode in Firefox Unsent crash reports in Firefox Firefox hangs or is not responding - How to fix Rebuilding the Global Database Task Manager - see whether tabs or extensions are slowing down Firefox What is the Mozilla VPN kill switch? How to let Firefox use the internet on your Windows computer Troubleshoot and diagnose Firefox problems Where to go for developer support How Thunderbird for Android avoids leaking your IP address to SMTP servers Troubleshoot security error codes on secure websites Warning Unresponsive script - What it means and how to fix it Certificate contains the same serial number as another certificate Thunderbird makes unrequested connections Certificate warnings in Firefox for iOS Firefox DNS over HTTPS DNS over HTTPS (DoH) FAQs Connecting to unsecured networks while using Mozilla VPN Joining public WiFi while on Mozilla VPN Troubleshooting speed issues on Mozilla VPN How to enable Always-on VPN on Android X-Mouse Button Control in Firefox 110 How to fix the Update Failed error message when updating Firefox Use the Troubleshooting Information page to help fix Firefox issues Quick fixes if your Firefox slows down Mozilla Crash Reporter TB How to reset the default user agent on Firefox Some videos won't play in background Drag and Drop errors with Firefox Launcher Process enabled and Windows UAC disabled - How to Fix Troubleshoot Mozilla VPN connection problems HTTPS-First upgrades to secure connections Crash reports in Firefox for iOS Websites look wrong or appear differently than they should Firefox takes a long time to start up Firefox uses too many CPU resources - How to fix Websites say that Firefox is outdated or incompatible even though it's the latest version Firefox says it's just updated every time it starts - how to fix Firefox does not work - Common fixes to get you back up and running "Firefox is already running but is not responding" error - How to fix Memory constraints, Firefox performance and Firewalls Rebuilding Global Database What do the security warning codes mean? How to resolve weak crypto error messages on Firefox 64-bit Firefox crashes with Citrix's XenApp VM How do I report a broken site in Firefox desktop? Disable Firefox Sync How to obtain the Mozilla VPN Logs Profiling Thunderbird Performance Report a broken website in Firefox for iOS Firefox for iOS won't load web pages How to fix an error when trying to open Telegram or Slack on Firefox Compacting folders - Potential complications Solutions for "Can not create temp folder archive" error when installing Firefox (Windows 10) Fritz!box isn't working when Mozilla VPN is on Identify problems caused by third-party modules in Firefox for Windows Unload inactive tabs to save system memory in Firefox The language of the websites I visit changes when I turn Mozilla VPN on - What to do Difficulties opening or using a website in Firefox 100 Difficulties opening or using a website in Firefox Focus for Android 100 How do I contact MDN Plus support? How can I help submit and resolve bugs in the MDN content repo? Where can I get help with the MDN API and documentation? Why do I see a white screen after updating Mozilla VPN to version 2.8.3? Firefox hangs when copying with Suggested Actions enabled on Windows 11 - What to do How do I report an issue with Firefox Relay? RCS messaging and Mozilla VPN Firefox blocked by macOS 15 Sequoia firewall - What you need to know Address screen sharing issues with Firefox on macOS 15 Sequoia Unsent crash reports in Firefox for Android Troubleshoot Firefox crashes (closing or quitting unexpectedly) Firefox is stuck in Troubleshoot Mode Firefox repeatedly opens empty tabs or windows after you click on a link Fix video and audio problems on Firefox for Windows N editions Avoid crashes - Tips and tricks Problems with email and how to find help Firefox keeps crashing at startup Home page with pipe character opens extra tabs when Firefox starts How to run Firefox when your profile is missing or inaccessible