try to set accessibility.blockautorefresh. to false in about:config

This can be caused by the connection settings having the default setting. Try to select the "No Proxy" setting instead of the default "Use the system proxy settings" setting. *Tools > Options > Advanced : Network : Connection > Settings *https://support.mozilla.org/kb/Options+window+-+Advanced+panel ----- Clear the cache and the cookies from sites that cause problems. "Clear the Cache": *Tools > Options > Advanced > Network > Cached Web Content: "Clear Now" "Remove Cookies" from sites causing problems: *Tools > Options > Privacy > Cookies: "Show Cookies"