I have also tried different profile nothing works.

Can you login to the Mozilla Account via this web page? *https://accounts.firefox.com/signin *https://accounts.firefox.com/settings

You can check the connection settings and check for possible issues with a Proxy or VPN service. *Settings -> General -> Network: Connection -> Settings If you do not need to use a Proxy to connect to internet, select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly. See also: *https://support.mozilla.org/en-US/kb/connection-settings-firefox *https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors Reboot the computer into Windows Safe Mode with network support to see if that has effect. *[https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/] *[https://www.digitalcitizen.life/4-ways-boot-safe-mode-windows-10/]