Troubleshooting steps for this error in Diablo III

Unexpected Blizzard Update Agent errors.

You have attempted to connect to an invalid server. If this problem persists, please contact Customer Support.

Information on Error BLZBNTAGT00001399

How to troubleshoot login problems with the Error Code 7

Information on error BLZBNTBNA000007D0

Information on error BLZBNTBNA000003E8

This error occurs when you have connected to our patch server but you cannot download patch information.

We're having trouble starting the Battle.net desktop app. Please try again. If the problem persists, try restarting your computer.

Troubleshooting steps for connection issues in Diablo II: Resurrected