Something went wrong with a security certificate. 
Error Code: BLZBNTBNA00000640 can't confirm that it has a secure connection to the servers.

  1. Press reload to refresh the page. If the issue persists, restart the client to clear up any temporary issues.
  2. If you experience connectivity issues, try optimizing your internet connection.
  3. Run security software to remove malware and viruses.
  4. Run Software Update to install pending security updates that may help address issues with malware on your computer.
  5. If the issue persists, uninstall and download a new copy from Account Management.

Tried everything here?

If you have tried all of these steps and still require assistance, visit our Technical Support Forum (World of Warcraft) (StarCraft II) (Diablo III) (Hearthstone) (Heroes of the Storm) (Overwatch) or contact us.