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 > Preferences > Advanced > Network > Cached Web Content: "Clear Now" "Remove Cookies" from sites causing problems: *Firefox > Preferences > Privacy > "Use custom settings for history" > Cookies: "Show Cookies" ----- See also: *http://kb.mozillazine.org/Cookies *https://support.mozilla.org/kb/Deleting+cookies