Re: Error code 216
EDIT - SOLVED ISSUE
This is not a problem with the game but steam, follow the steps below to fix the problem in Steam.
Specifying a Clientport as a Launch Option
To specify a client port, please perform the following steps for each computer on the LAN
Go to Steam's My games menu
Right-click on the game you wish to play
Go to Properties
From the General tab, click on the Set launch options button
Add a different client port number on each machine between 27005 and 27032 in the following format:
+clientport 270XX
Note: Do not use 27020
Click OK
NOTE: This solution only works if you launch the game through the My games menu.
If you have already set other launch options, leave a space between the last character of your previous launch option and the + of your clientport setting.
Following these steps allowed us to play together no issues at all.
/EDIT
Same issue, trying to play on PC with my wife in the same house, wired connections to a single router.
We've been able to get in 3 matches together but one or both of us will disconnect with error 216 on the majority of matches we try to join. It's not consistent on who disconnects, doesn't seem to matter who is leader of the party.
We don't have any issue joining games solo and when I tried to join her game when there was an open spot, she was immediately disconnected.