I do not know where to officially log a bug report, perhaps someone can point me to the correct URL. But here goes.
Reproducible Steps:
Follow these instructions:
https://wiki.unrealengine.com/How_To…ons_In_C%2B%2B
Now change the DefaultEngine.ini to use the Steam Online Subsystem instead of the NULL Online Subsystem:
[/Script/Engine.GameEngine]
+NetDriverDefinitions=(DefName=“GameNetDriver”,DriverClassName=“OnlineSubsystemSteam.SteamNetDriver”,DriverClassNameFallback=“OnlineSubsystemUtils.IpNetDriver”)
[OnlineSubsystem]
DefaultPlatformService=Steam
PollingIntervalInMs=20
bUsesPresence=false
[OnlineSubsystemSteam]
bEnabled=true
; Your actual app id goes here.
SteamDevAppId=480
bUsesPresence=false
[/Script/OnlineSubsystemSteam.SteamNetDriver]
NetConnectionClassName=“OnlineSubsystemSteam.SteamNetConnection”
If you now launch the game, you will see the Steam overlay, which is correct and shows that Steam is indeed enabled.
But now if you invoke FindSessions (however you wish - a UFUNCTION(Exec) which calls it is convenient, you will get 0 sessions back, and entries similar to the following will be seen in the Output window:
LogOnlineSession: Warning: STEAM: Server response IP:91.214.119.165
LogOnlineSession: Warning: STEAM: Removed incompatible build: ServerBuildUniqueId = 0x00000000, GetBuildUniqueId() = 0x00a14c28
LogOnlineSession: Warning: STEAM: Server response IP:85.175.101.35
LogOnlineSession: Warning: STEAM: Removed incompatible build: ServerBuildUniqueId = 0x00000000, GetBuildUniqueId() = 0x00a14c28
LogOnlineSession: Warning: STEAM: Server response IP:41.33.181.123
I believe this to be a bug. I have spend many hours trying to solve this, to no avail. The warning message is pretty much useless because I could find no documentation, in the Unreal docs or anywhere else, that explains what this message means and why it occurs and how to resolve it. So even if this is not a bug, I would expect the UE4 docs for the online subsystem Steam to then at least discuss these build IDs and to explain what it means and why they should match and how to make them match.
Thanks,
Marius.