Are you possibly using a VPN or proxy ? You can check the connection settings. *Settings -> General -> Network: Connection -> Settings If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly. See "Firefox connection settings": *https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors *https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can *https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites You can also check these security.tls on the <b>about:config</b> page and make sure they are default (i.e. not bold). *security.tls.version.max 4 *security.tls.version.min 3 *https://support.mozilla.org/en-US/kb/about-config-editor-firefox