2 player campaign connection problem

Level 1
Dec 25, 2017
A friend and I wanted to play the 2 player campaign so we both downloaded the newest version of Frozen Throne. We tried to connect over LAN and WIFI but it only works for about a minute and then on of us gets kicked out of the map0. The thing is that the connection works absolutely fine for other maps (tower defense etc.)
Could the problem be that one of us is playing on mac and the other one on windows? If so can anyone please help us finding a solution.