Hello, from this post:h ttps://support.mozilla.org/en-US/questions/1158414 Clear the cache and remove the cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences). "Clear the cache": * Firefox/Options/Preferences -> Advanced -> Network -> Cached Web Content: "Clear Now" "Remove the cookies" from websites that cause problems. * Firefox/Options/Preferences -> Privacy -> "Use custom settings for history" -> Cookies: "Show Cookies" Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button# or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem. * switch to the DEFAULT theme: "3-bar" menu button# or Tools -> Add-ons -> Appearance * do NOT click the "Refresh Firefox" button on the Safe Mode start window * https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode * https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems