Steam Online Subsystem not working in packaged build (UE5.6)

Development Platform & Builds
, , ,
1

I’m testing multiplayer with the Steam Online Subsystem in Unreal Engine 5.6. Everything works fine inside the editor, but when I run the packaged build, it doesn’t connect to Steam.

In the logs I get these warnings:

LogSteamShared: Warning: SteamAPI failed to initialize, conditions not met.
LogOnline: Warning: STEAM: Steamworks: SteamUtils() failed!
LogOnline: STEAM: [AppId: 0] Client API initialized 0
LogOnline: OSS: Unable to create OnlineSubsystem instance STEAM

What I’ve tried:

  • Created steam_appid.txt with 480 inside.

  • Placed steam_api64.dll next to the EXE.

  • Running the build with the Steam client open.

Issue:
When I try to host a game, it seems to enter the map for a split second and then immediately kicks me back to the main menu.