Arkan,
We’ve forwarded feedback that the error message could be more clear, but unfortunately it is incorrect and as a result we can’t help with it. Activision knows better than us what things will cause connection problems with their games. Ultimately it’s not up to us to help fix connectivity issues that you experience while playing this game since it’s not our game. We are simply a platform provider for this game - we get the data to your PC.
Caterpepi already posted the link regarding our scope of support, but here it is in case you missed it. At this point your only recourse is going to be working with Activision to correct any connectivity issues with the game.