I’m not sure if this will help anyone, but I had the same issue and couldn’t find a solution after searching through forums and trying everything. I decided to try something, and it worked for me, so I hope it helps others as well.
Here’s what to do:
- Log out of Battle.net.
- In the login window, click the gear icon above your email.
- Select “Continue without logging in.”
- Start Starcraft 2.
- Once the game launches, log in with your account in-game.
This method worked for me, and I hope it resolves the issue for others too!