[2020] Launcher and log-in

Looking at that URL you are trying to sign into an internal Paradox server (sandbox), which does not use standard Paradox logins. Are you in a beta programme or something?

BTW you should opt out of the launcher beta as 2020.14 is the public version now.  

Toggling beta off and reinstalling the launcher ought to get you onto 2020.14 now.