Couldn't establish network communication with server

[Vavyman]

Hi guys, having an issue with multiplayer on my home network, tried all the usual but I am sure yall gonna ask so tell me what logs ya want and Ill dig em out. I always get "Couldn't establish network communication with server" but it used to work like 3 months ago and nothing changed my end.. and yes i searched forums and nothing helps and or no fixes...

1 Me and room mate have it on steam..
2 all versions on win32 win 64 win 7 win 8 win 10 and mac are all affected,
3 no it is not my router, flattened it and set static IP's for all devices and port forwarded the ports to static addresses, also used external IP for connect nothing helps

Would really appreciate helps on this as I am at the end of my patience now

Thanks in advance