I think everything is done correctly; the IVC server is hosted by the game server and web hosting, I enter his IP for both the game and IVC server, and both our games launch the IVC client and connect.
When he keys his mic I can hear him through the comms just fine, but he can’t hear me at all, neither speech nor the key mic sound. The server console appears to recognize that I’m transmitting, but he doesn’t hear it. Is there something we messed up during setup?
Edit: for those who have the same issue, the solution was unfortunately that the issue simply fixed itself. The next time we tried it, it worked fine. Hopefully the troubleshooting steps others have put will be useful.