How do I get Steam Multiplayer working on Mac?

I’ve followed the documentation here: UE4 Docs Online Subsystem and made the changes to my DefaultEngine.ini file and used Steamworks SDK v139 (and later v146 in a newer engine build),

I’ve installed the Advanced Sessions and Advanced Steam Sessions plugins, and I’ve followed this Youtube tutorial to setup a multiplayer project,

I’ve duplicated the project in UE4 4.21 and 4.23 (in case it was an engine problem),

I’ve packaged the project and ran it through Steam (development build), as well as locally using the dedicated server option with 2 players,

But nothing works. I want to create a game on one screen, and join the game from another but I cannot do this.

Running locally with a dedicated server (with the 2 player option), I was able to start a game and move around, but this warning showed up in the logs:

LogOnlineSession: Warning: OSS: No game present to leave for session (GameSession)

I wasn’t able to connect to that game session with the other screen, this is the the log output when trying to join:

LogSockets: Warning: GetAddressInfo failed to resolve host with error SE_HOST_NOT_FOUND [8]

LogOnline: Verbose: OSS: Sending 16 bytes to

LogOnline: Verbose: OSS: Sent query packet…

LogOnline: Verbose: OSS: Received 16 bytes from

LogOnline: Verbose: OSS: Received 16 bytes from

LogOnline: Verbose: OSS: Sending 192 bytes to

LogOnline: Verbose: OSS: Received 192 bytes from

LogOnline: Verbose: OSS: Received 192 bytes from

LogScript: Script Msg: Found a session. Ping is 33

LogOnlieSession: Warning: OSS: Invalid session info for session GameSession in GetResolvedConnectString()

I can provide zips of the UE4 4.21 and 4.23 projects, but they’re almost identical to the Youtube example.

I’m very new to using UE4 and I’ve been trying to get this working for several weeks now but I’ve come to a dead-end, I’d really appreciate if anyone could help me out, thank you.

Hi there! Did you ever get this working? I’m having problems getting my project, which runs on Steam Online Subsystem, to work on Mac (it can’t find any hosted sessions), but it works fine over 2 Windows PC. I made the changes in DefaultEngine.ini and added it to Steam as well. I think I must be missing a key set up for Mac since it works on PC.