The issues reported earlier by Blizzard have now been resolved:
If you are still having problems logging in, please start with these connection troubleshooting steps (click here).
This was posted on the Blizzard Customer Service Twitter feed:
This includes any “Unable to log-in”, “Timeout from communicating” and “No Overwatch License Found” error messages you may see.
Please hang tight everyone!
Additional Updates from Lead Engineer Bill Warnecke: