Hey there,
I understand that this is a fresh install of Starcraft 2, but I’m curious if it’s related to an issue we’ve been seeing where the Public Test Realm exe is interfering with the login process.
Can you take a look at the steps here and see if you have the PTR showing up? If so, try removing it and then see if it will let you log in.
If that doesn’t do the trick, make sure that on the Battle.net app you have Starcraft II selected above the Play button and that it’s set to the Americas region.