Hey,
I have checked the internet für your problem.
May the reason is the blizzard-patcher. On their website they have this hints:
1.) Launch the patcher as an Admin
2.) Perform repair
3.) Perform ipconfig /flush dns, ipconfig /release, ipconfig /renew in admin cmd
4.) Cleared/deleted cache/battle.net folders
5.) Open port 3074
6.) Uninstalled/Re-Installed on different drive
You can also have a look on the activision Support-Site. You can find your error-Code on this site.