This issue can be caused by corrupted cookies or cookies that are blocked. *check the permissions on the about:permissions page and in "Tools > Page Info > Permissions" *https://support.mozilla.org/kb/fix-login-issues-on-websites-require-passwords Clear the cache and remove cookies only from websites that cause problems. "Clear the Cache": *Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now" "Remove Cookies" from sites causing problems: *Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies" If clearing cookies didn't help then it is possible that the cookies.sqlite file that stores the cookies got corrupted. *Rename (or delete) <b>cookies.sqlite</b> (cookies.sqlite.old) and delete other present cookies files like <b>cookies.sqlite-journal</b> in the Firefox profile folder in case the file cookies.sqlite got corrupted. You can use this button to go to the currently used Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox