Try again later
   Check your network connection
   Check that Firefox has permission to access the web (you might be connected but behind a firewall)

My computer is Widnows 10 Pro, firefox have been running well for years. Since yesterday, it starts to show: Hmm. We’re having trouble finding that site. We can’t connect to the server at www.youtube.com. If you entered the right address, you can: Try again later Check your network connection Check that Firefox has permission to access the web (you might be connected but behind a firewall) No matter which site I go, same error. I have tried creating a new profile, disabled firewall, no proxy, no extension, even uninstall/reinstall firefox. Issue remain the same. Only time it works is right after I reboot the computer, then it works for a while (somewhere around 5-10 minutes). Computer never sleep, and it will acts up during my browsing. All my other browsers, outlook or application that access the internet works fine. Windows Defender scan no virus.