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How to enable Always-on VPN on Android Unsent crash reports in Firefox Rate your Firefox experience, surveys and out of date messages (Heartbeat) How to obtain the Mozilla VPN Logs Report Site Issues on Firefox for iOS Compacting folders - Potential complications Solutions for "Can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