Summary
After setting my project up as suggested I am not able to host a listen server on my Macbook. When I host on my PC I can join through the Mac but hosting does not work. In the logs all the normal Steam lines print suggesting success but then it just hangs and after 2 minutes the join fails.
Other people seem to be having this issue. One interesting thing I found is that in the ‘Using Steam Sockets’ Documentation theres a note saying ‘In Unreal Engine 4.27.0, an issue with the FUniqueNetIdSteam structure prevented Steam Sockets from creating successful connections. This issue is fixed in 4.27.2 and later’. I might be wrong but I feel as though this might have returned because in the logs it also says there is a bad UniqueNetID. However, still not sure why the Windows hosting would still work with this error showing but thought it worth mentioning.
What Type of Bug are you experiencing?
Networking
Steps to Reproduce
- Create Unreal Engine 5.7.4 project.
- Enable Steam Sockets in Plugins.
- Create session creation/hosting/finding user interface/setup.
- Package Mac Build on Mac in Unreal Engine 5.7.4
- Upload to Steam or test with steam_appid.txt with 480 in same folder as .exe.
- Start game on Mac and start a hosted session
- Attempt to join that session on other device (Mac/Windows)
Expected Result
When join session attempted the expected results is to be able to join the hostes session.
Observed Result
The logs suggest the join is successful but the client/joining device just hangs and after 2 minutes the log shows failure to connect/join.
Affects Versions
5.8
5.7
Platform(s)
Mac
Windows
Additional Notes
Some logging but this isnt too helpful because it seems to suggest success when there isn’t any:
[2026.10.04-08.57.31:835][369]LogNet: InitBase PendingNetDriver (NetDriverDefinition GameNetDriver) using replication model Generic
[2026.10.04-08.57.31:836][369]LogNet: SteamSocketsNetConnection_2147482323 setting maximum channels to: 32767
[2026.10.04-08.57.31:836][369]PacketHandlerLog: Loaded PacketHandler component: OnlineSubsystemSteam.SteamAuthComponentModuleInterface ()
[2026.10.04-08.57.31:836][369]PacketHandlerLog: Loaded PacketHandler component: Engine.EngineHandlerComponentFactory (StatelessConnectHandlerComponent)
[2026.10.04-08.57.31:837][369]LogHandshake: Stateless Handshake: NetDriverDefinition ‘GameNetDriver’ CachedClientID: 5
[2026.10.04-08.57.31:837][369]LogSteamSocketsAPI: Warning: SteamSockets API: Warning [#2184722012 P2P steamid:76561199184811405 vport 7777] Relay candidates enabled by P2P_Transport_ICE_Enable, but P2P_TURN_ServerList is empty
[2026.10.04-08.57.31:840][369]LogSockets: SteamSockets: Now tracking socket 2184722012 for addr 76561199184811405:7777, has parent? 0
[2026.10.04-08.57.31:840][369]LogNet: Game client on port 7777, rate 100000
[2026.10.04-08.57.31:840][369]LogNetVersion: ProjectIdle 1.0.0.0, NetCL: 47537391, EngineNetworkVersion: 43, GameNetworkVersion: 0 (Checksum: 2643196055)
[2026.10.04-08.57.31:843][370]LogRHI: Display: Encountered a new graphics PSO: 863310323
[2026.10.04-08.57.32:649][809]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P steamid:76561199184811405 vport 7777] finding route
[2026.10.04-08.57.32:777][877]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P steamid:76561199184811405 vport 7777] Requesting session from syd#412 (103.10.125.41:27048). Ping = 60 = 32+0+28 (front+interior+remote). Rank=1 Score=-1
[2026.10.04-08.57.32:846][912]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P steamid:76561199184811405 vport 7777] Selecting syd#412 (103.10.125.41:27048) as primary. (Ping = 60 = 32+0+28 (front+interior+remote). Rank=1 Score=66)
[2026.10.04-08.57.32:880][929]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P SDR steamid:76561199184811405 vport 7777] Requesting session from sea#40 (205.196.6.135:27054). Ping = 271 = 134+0+137 (front+interior+remote). Rank=2 Score=-1
[2026.10.04-08.57.32:953][968]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P SDR steamid:76561199184811405 vport 7777] connected
[2026.10.04-08.57.32:957][968]LogSteamSocketsAPI: Verbose: SteamSockets API: Log DualWifi not detected. We won’t try again. Didn’t find any Dual-Wifi-capable Wifi adapters
[2026.10.04-08.57.33:015][998]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#2184722012 P2P SDR steamid:76561199184811405 vport 7777] Selecting sea#40 (205.196.6.135:27054) as backup #1 (Ping = 271 = 134+0+137 (front+interior+remote). Rank=2 Score=298)
[2026.10.04-08.57.37:117][204]LogSlate: Request Window 'ProjectIdle (64-bit Development PCD3D_SM6) ’ being destroyed
[2026.10.04-08.57.37:118][204]LogSlate: Window 'ProjectIdle (64-bit Development PCD3D_SM6) ’ being destroyed
[2026.10.04-08.57.37:122][204]LogWindowsTextInputMethodSystem: Activated input method: English (New Zealand) - (Keyboard).
[2026.10.04-08.57.37:131][204]LogOnlineSession: Warning: STEAM: Player FlettyPeabody [0x1100001074A3857] is not part of session (GameSession)
[2026.10.04-08.57.37:131][204]LogOnlineSession: Warning: STEAM: Player FlettyPeabody [0x1100001074A3857] is not part of session (GameSession)
[2026.10.04-08.57.37:131][204]LogSlate: Updating window title bar state: overlay mode, drag disabled, window buttons hidden, title bar hidden
[2026.10.04-08.57.37:131][204]LogEngine: All Windows Closed
[2026.10.04-08.57.37:131][204]LogWindows: FPlatformMisc::RequestExit(0, UGameEngine::Tick.ViewportClosed)
[2026.10.04-08.57.37:131][204]LogWindows: FPlatformMisc::RequestExitWithStatus(0, 0, UGameEngine::Tick.ViewportClosed)