I have had this problem with Rome Total War 2 and have just discovered that I also have it on Attilla, but for some reason I don't have it with Shogun 2.
When I attempt to host a campaign, I get an error message that says 'failed to host game'
. I get the same message for online and local network hosts. Trying to join another game tells me that the host game is unavailable.
I've already enabled all the permissions on my firewall for my total war games and done a complete clean install for Attilla and Rome- any help would be very appreciated!