The open beta has begun and we've been extremely successful in that we've already managed to break a few things. We've capped the open beta concurrency until we can resolve some stability and service issues, and until it's resolved you will likely see an Error 37 when attempting to log in.

Error 12 - This is an error we're still investigating but you can workaround it by simply changing your Battle.net account password to force your account information to refresh. Once changed you can change it back.
Error 3003 - Click Options, under Account change your region to The Americas. The open beta is only being held on US hardware.
Error 315300 - If you're sure you're typing your correct account information, check to ensure no additional spaces were added before or after your email address. If that doesn't work try a completely wrong account name and wrong password, error, and then again try your correct Battle.net account email and password.
Error 24000 - Once logged in you may run into this error when attempting to start a game. We're aware and are working to resolve it as quickly as possible.
Gray login button - You need to use your Battle.net email address as your account name. Your BattleTag is a nickname, not your account name.
Updating Setup Files - If you're stuck on "Updating Setup Files" try these troubleshooting steps.
Crashes - For any crashes please visit the Technical Support forum