Hi, I saw this topic is relatively fresh. I have a similar error with ZH (Gentool): I can start and connect, the game starts for 1 second, then all players are counting down (but I am the problem). I played happily for months and did not change anything, i just did not use my laptop for 6 weeks.
I read somewhere about port forwarding, but my router does not seem to support this.
Please let me know if and how you have solved this, or what is the other topic i should visit.