Incorrect Auth Key? Network Problems?

[VengenceMkII]

Granted I've seen this asked beforehand but this is an interesting issue for me. I apologize if this may be the wrong topic but I don't see 'Fire and Sword Tech Support' as a thread.

First of all, I tried joining the official TW Captain Co-Op servers and this worked just fine. I got ingame, messed around. Now here comes the crazy part. My friend and I were going to play a private match and he sets up a game. I try to join and I get the Incorrect Authorization Key error. Crazy yes? So I make my own game and he tries to join and HE gets that error! Wacked out ya? We then tried Hamachi, same issue. I tried pinging him but I noticed that I couldn't reach him. So this leads me to the current questions:

Both of our keys are legit

I have F&S from TW direct, he has it from steam. Does that cause issues?
He has his router forwarded but I have no access to mine to do such things. Could a router not forwarded cause this? DESPITE me being able to join official servers?
Is there some kind of hidden problem I am not seeing?

EDIT:

Additionally my friend was able to have other people to join his server so he has no issues.

 

[RaidenHitsu]

Yeah I've got the same exact problem, the only difference is that my friend has steam version like myself.

 

[sapped]

same problem, I always get it when joining non dedicated servers, whats wrong!!!

 

[Ozyton]

Keep in mind that other people were able to join the server just fine, so the server is definitely open to others and shows up in the server list.

 

[Ozyton]

Is there really no information about this?