Since this morning I have been unable to contact any website via Fire Fox. René

Hi What happens when you try? Is there any error message?

Try to start Firefox in <b>Troubleshoot Mode</b> to see if that works. *Windows: hold down the Shift key while starting Firefox *Mac: hold down the Options key while starting Firefox *https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode 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/]