[15.34] couldn't establish network communication with server

[ThomasAskov]

My friend cant join my game and we have no idea why?
I created this multiplayer game but every time he tries to join it just says "couldn't establish network communication with server"
We have tried nearly 20 different things (changing Firewall settings)(we got hamachi to work but the more we build the longer it took for him to join. when we had set up a small factory with electronic circuits i could take around 2 hours for him to join the next day, and the connection kept dropping out so he had to wait again). The download speed was like 0.5 - 2 kb and it had to download about 200 megabytes or something like that.
A few days later one of my other friends tried joining my game but this time i worked. We could play with no problems at all. it didnt need to download anything this time for some reason.
The funny thing is i havent changed Router settings or port forward.

Any help would be greatly appreciated
-Thomas

[daniel34]

UDPSocket.cpp:460: Recvfrom failed (but can be probably ignored): En eksisterende forbindelse blev tvangsafbrudt af en ekstern vært.

(An existing connection was forcibly interrupted by an external host.)

I'm not sure if that is your log or your friends log, but some kind of firewall is interrupting the communication. Also check for software like Hamachi which creates additional network interfaces, you should be able to see them by right-clicking the network icon on the bottom right, then open the Network and sharing center, then go to "Change adapter settings".

If there are no unknown (TAP and VPN) adapters, then I'm sorry and can't help you. However the reason is somewhere on your system and prevents Factorio from using the network.