Steam dedicated server api not working/missing Steam DLL's in dedicated server build.

Development Programming & Scripting Multiplayer & Networking
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1

Hi,

We have recently upgraded our project from Unreal Engine 5.5.4 to 5.6. Our game uses a dedicated server and the Steam online subsystem to allow players to play together. After upgrading to 5.6 and generating a server build to run on our dedicated server we noticed it failed and we are unable to create a server or join a server as one of the clients, and we now get the following warning in our dedicated servers console:

[Image Removed]

After digging into this further we noticed that, when compared to a previous server build from 5.5.4, a bunch of DLL files and PDB files were missing from both the server builds binaries/win64 folder and the projects binaries/win64 folder. The missing files are as follows:

Missing DLL’s and files in packaged game folder:

  • [PROJECT_NAME]/binaries/win64/steam_api64.dll
  • [PROJECT_NAME]/binaries/win64/boost_Atomic-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_chrono-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_filesystem-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_iostreams-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_program_options-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_python311-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_regex-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_system-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/boost_thread-mt-x64.dll
  • [PROJECT_NAME]/binaries/win64/sdkencryptedappticket64.dll
  • [PROJECT_NAME]/binaries/win64/tbb.pdb
  • [PROJECT_NAME]/binaries/win64/tbbmalloc.pdb

Missing DLL’s and files in project folder:

  • game/binaries/win64/steam_api64.dll
  • game/binaries/win64/boost_Atomic-mt-x64.dll
  • game/binaries/win64/boost_chrono-mt-x64.dll
  • game/binaries/win64/boost_filesystem-mt-x64.dll
  • game/binaries/win64/boost_iostreams-mt-x64.dll
  • game/binaries/win64/boost_program_options-mt-x64.dll
  • game/binaries/win64/boost_python311-mt-x64.dll
  • game/binaries/win64/boost_regex-mt-x64.dll
  • game/binaries/win64/boost_system-mt-x64.dll
  • game/binaries/win64/boost_thread-mt-x64.dll
  • game/binaries/win64/OpenColorIO_2_3.dll
  • game/binaries/win64/sdkencryptedappticket64.dll
  • game/binaries/win64/tbb.pdb
  • game/binaries/win64/tbbmalloc.pdb

We are aware of the issue outlined on the bug tracker that the “SteamNetDriver” and “SteamNetConnection” classed have been moved from the “OnlineSubsystemSteam” module to the “SocketSubsystemSteamIP” module (https://issues.unrealengine.com/issue/UE-297279) but after modifying our DefaultEngine.ini file to match this it has had no effect, so I’ll also attach both our 5.5.4 DefaultEngine.ini as well as our new 5.6 DefaultEngine.ini

Any help with this issue would be greatly appreciated as we need this functionality working for our players to play our game, and if any additional info is required please let me know!

2

Steps to Reproduce
To reproduce the issue, you can download the provided repro and add it to a source version of the engine. Then package the project using the server target and you will see that the mentioned DLL files (that were previously generated in the folders mentioned in the issue post) do not exist in the folders, and if this build was distributed to Steam and downloaded to be ran on a dedicated server the error that was linked will occur due to what I assume is the missing DLL’s.

Note: I have removed our Steam app ID from this test project and the linked .ini files and replaced it with the default Steam app ID of 480.

3

Hi,

Thank you for the report. As we look into this, I wanted to double check some things.

First, do you have the SteamSockets plugin enabled for your project? The test project provided here does not seem to enable this.

Next, is your project using the SteamNetDriver or SteamSocketsNetDriver? The test project is using the SteamNetDriver, which is much older, and we generally recommend using the SteamSocketsNetDriver now instead (we have an open task to update this in the documentation).

Thanks,

Alex

4

Hi Alex,

We did also try usingthe Steam Sockets plugin and net driver instead of the SteamNetDriver however I believe we still encountered the same issue. I’ll swap to SteamSockets now following the documentation and give it another try, and then I’ll post our dedicated server log with SteamSockets and the updated test project!

Thanks!

5

After adding the SteamSockets plugin and following the documentation (https://dev.epicgames.com/documentation/en\-us/unreal\-engine/using\-steam\-sockets\-in\-unreal\-engine) we still get the same warnings mentioned before:

LogSteamShared: Warning: Steam Dedicated Server API failed to initialize.

LogOnline: STEAM: [AppId: 0] Game Server API initialized 0

LogOnline: Warning: STEAM: Failed to initialize Steam, this could be due to a Steam server and client running on the same machine. Try running with -NOSTEAM on the cmdline to disable.

LogOnline: Display: STEAM: OnlineSubsystemSteam::Shutdown()

LogOnline: Warning: STEAM: Steam API failed to initialize!

LogOnline: Display: STEAM: OnlineSubsystemSteam::Shutdown()

LogOnline: OSS: Unable to create OnlineSubsystem instance STEAM

and we now also get the following errors relating to SteamSockets:

[2025.08.07-08.34.26:645][ 0]LogSockets: Warning: Unable to load SocketSubsystem module SteamSockets

[2025.08.07-08.34.26:646][ 0]LogUObjectGlobals: Warning: Failed to find object ‘Class /Script/SteamSockets.SteamNetSocketsNetDriver’

[2025.08.07-08.34.26:646][ 0]LogNet: CreateNamedNetDriver failed to create driver from definition GameNetDriver

[2025.08.07-08.34.26:646][ 0]LogNet: CreateNamedNetDriver failed to create driver GameNetDriver from definition GameNetDriver

[2025.08.07-08.34.26:646][ 0]LogNet: Error: UEngine::BroadcastNetworkFailure: FailureType = NetDriverCreateFailure, ErrorString = , Driver = NONE

[2025.08.07-08.34.26:647][ 0]LogNet: NetworkFailure: NetDriverCreateFailure, Error: ‘’

I have attached the full output log as well as the same example project with the updated DefaultEngine.ini (with our SteamAppID replaced with the default of 480). Please let me know if there is anything that needs changing in the DefaultEngine.ini and, if so, I can make those changes and get you an updated log.

6

Follow up as I can only add one attachment per reply. Here’s the updated test project:

7

Hi,

Thank you for the additional logs and test project. After discussing this with another dev more familiar with the Steam OSS, it seems as though this could be an issue with the app ID.

We’ve opened an internal task to look into why this file isn’t being generated, but in the meanwhile, you may be able to work around the issue by manually including a “steam_appid.txt” file containing the app ID into the server executable’s directory.

Thanks,

Alex

8

Hi,

Thanks for looking into this for us, after manually adding the “steam_appid.txt” with the app ID of our Steamworks app we no longer get the warning of “Steam Dedicated Server API Failed To Initialize”. The server will however still not create a session, and we get the following in the output log, warning us of an unexpected GSPolicyResponse callback:

[2025.08.12-08.05.58:139][ 0]LogInit: Display: Engine is initialized. Leaving FEngineLoop::Init()

[2025.08.12-08.05.58:139][ 0]LogLoad: (Engine Initialization) Total time: 0.72 seconds

[2025.08.12-08.05.58:175][ 0]LogTrace: Display: Control listening on port 36169

[2025.08.12-08.05.58:307][ 5]LogSteamSocketsAPI: Warning: SteamSockets API: Warning SDR network config fetch attempt #1 failed. HTTP 504. . Trying again.

[2025.08.12-08.05.58:611][ 14]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Got SDR network config. Loaded revision 1753321443 OK

[2025.08.12-08.05.58:611][ 14]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Performing ping measurement

[2025.08.12-08.05.58:612][ 14]LogSteamSocketsAPI: Verbose: SteamSockets API: Log SDR RelayNetworkStatus: avail=Attempting config=OK anyrelay=Attempting (Performing ping measurement)

[2025.08.12-08.05.59:184][ 31]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Gameserver logged on to Steam, assigned identity steamid:90272478879571997

[2025.08.12-08.05.59:184][ 31]LogSteamSocketsAPI: Verbose: SteamSockets API: Log AuthStatus (steamid:90272478879571997): Attempting (Requesting cert)

[2025.08.12-08.05.59:185][ 31]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Set SteamNetworkingSockets P2P_STUN_ServerList to ‘185.25.182.52:3478’ as per SteamNetworkingSocketsSerialized

[2025.08.12-08.05.59:489][ 39]LogSteamSocketsAPI: Verbose: SteamSockets API: Log AuthStatus (steamid:90272478879571997): OK (OK)

[2025.08.12-08.05.59:489][ 39]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Certificate expires in 48h00m at 1755158759 (current time 1754985958), will renew in 46h00m

[2025.08.12-08.05.59:490][ 39]LogOnline: Warning: STEAM: Unexpected GSPolicyResponse callback

[2025.08.12-08.06.02:903][141]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Ping measurement completed in 4.2s. Relays: 24 valid, 5 great, 10 good+, 18 ok+, 6 ignored

[2025.08.12-08.06.02:903][141]LogSteamSocketsAPI: Verbose: SteamSockets API: Log Ping location: lhr=4+0,ams=13+1/9+0,par=13+1/10+0,ams4=15+1/11+0,fra=18+1/18+0,sto2=32+3/28+0,vie=43+4/28+0,sto=31+3/29+0,mad=35+3/30+0,iad=78+7,sgp=168+16/169+16,gru=203+20/193+7

[2025.08.12-08.06.02:904][141]LogSteamSocketsAPI: Verbose: SteamSockets API: Log SDR RelayNetworkStatus: avail=OK config=OK anyrelay=OK (OK. Relays: 24 valid, 5 great, 10 good+, 18 ok+, 6 ignored)

[2025.08.12-08.06.13:153][443]LogOnline: Warning: OSS: Async task ‘FOnlineAsyncTaskSteamCreateServer bWasSuccessful: 0’ failed in 15.016753 seconds

[2025.08.12-08.06.13:154][443]LogGameSession: OnCreateSessionComplete GameSession bSuccess: 0

I’ll attach the full log to this message too for you but it seems to be atleast connecting to Steam now, we are just unable to create a session for our players to join!

9

I think it’s not only the “steam_appid.txt” that isn’t being generated, but also the aforementioned DLL files relating to Steam which should be generated when packaging the dedicated server that are missing from the build. I’m guessing because those DLL files aren’t present in the build that is uploaded to Steam that may be part of the reason why the appid file isn’t generating and why we cannot boot up a server!

10

Hi,

Thank you for the update and logs. I don’t believe the missing DLLs are related to this issue, as those were intended to be removed.

We do have a potential fix shelved at CL 44788599. Could you try integrating this change to see if it resolves the issue?

Thanks,

Alex

11

Morning Alex,

Thanks so much for that, we pulled in that shelf this morning and it seems to fix our issues, the server now boots up as expected and I’m able to see it in the Steam Game Servers list, as well as in our server browser and join it. I did still have to manually add the “steam_appid.txt” file to the folder that contains the server executable so that still isn’t auto generating, but for the time being until that is fixed we can use the workaround you gave us of manually adding it. Which future release will this these fixes (from CL:44788599 and the fix for generating the “steam_appid.txt”) be added to going forwards? as we will probably skip the versions between now and then and keep our current working version until this change is integrated into the engine?

Thanks again for all the help with this issue! :grinning_face:

All the best,

Cristian

12

Hi,

Great, I’m glad that fixed the problem!

That shelved change will likely be submitted soon, after some more testing and review. That being said, if you do run into any issues, please don’t hesitate to reach out.

As for the steam_appid.txt issue, this will require some more investigation, and so I can’t provide an estimate as to when a fix may be made.

Thanks,

Alex