Multiplayer not working, "failure to initialize online play"

[Віник Пушок]

So I and my friend have just bought this game, and we want to play it in co-op.

We both can launch the game just fine and play our own respective singleplayer games.

When he tries to pick "multiplayer" option, he can pick "online" and host a game, and then play just fine ("find game" can result in finding something random).

However, when I try to pick "multiplayer" and "find game", after a few seconds of load it says "failure to initialize online play". Then I can't even pick "online", only "local network".

He uses ENG language, I use RU language, if that's important.

[Skybreaker]

Hi Грицько,
when playing multiplayer, please make sure you that there is nothing restricting or even fully blocking your and your coop-buddy's connection.
So please have a look and check following:

• Check, if you have a stable internet connection. If you are using WiFi, use a wired/cable connection, if possible, to prevent any possible interruptions.
  
• Make sure you have enough bandwidth available. So disabling all downloads, streams, closing all tabs in your browser is recommended and check if no one else in your household might “steal” bandwidth.
  
• Check, if Steam and Vikings - Wolves of Midgard is not being restricted/blocked by your Anti-Virus program. Simply set exceptions for both applications.
  
• Check your Firewall/s (Router, Windows Firewall, additional Firewall, e.g. Norton) if exception are set for Steam and Vikings - Wolves of Midgard in addition.
  
• There are no specific ports needed to be enabled manually in your router.
  Nevertheless if your Router features the option “UPnP”, we would recommend to enable this option, as it simply enables programs, such as Games in general, which are using multiplayer, to open the ports needed on their own, without opening up huge ranges of ports.

-cheers

[П'яточок]

What would win: 2 hours of troubleshooting or restarting Steam?
Yep, you guessed correctly, the latter one actually solved our problem.

@Unerde, add that one to your copy-paste list of typical problems. It may save some other poor soul a lot of nerves and time.

-cheers