This error means the Battle.net Agent (the process that installs and patches our games) couldn't stream necessary files.
Troubleshooting steps for linking a Twitch.tv account with a Battle.net account.
How to unlink a Playstation Network, Xbox Live, or Nintendo Switch account from a Battle.net account
Your account is unable to log into Blizzard services.
Information about the error message "You can’t make this purchase because your previous purchase is under review" and troubleshooting steps
Before you can connect to the game servers, you must add a phone number to this account.