Join Session not working in 5.6 listen server (both steam and EOS)

Development Programming & Scripting Multiplayer & Networking
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1

Hello, in 5.6 joining session in build game failed on connection to the server by both methods: trying to connect via advanced steam plugin or EOS (dev tool). Creating session and finding sessions works fine.

  1. [2025.06.16-14.43.33:863][258]LogSockets: Warning: GetAddressInfo failed to resolve host with error SE_HOST_NOT_FOUND [11001]
  2. Always trying to load MainMenu map

EOS
[2025.06.16-14.43.33:855][258]LogGlobalStatus: UEngine::Browse Started Browse: “EOS:00025b221d9c4558a195d6e72d7e30af:GameNetDriver:97/Game/Maps/MainMenu”
[2025.06.16-14.43.33:855][258]LogNet: Browse: EOS:00025b221d9c4558a195d6e72d7e30af:GameNetDriver:97/Game/Maps/MainMenu
[2025.06.16-14.43.33:855][258]LogCsvProfiler: Display: Metadata set : iris=“0”
[2025.06.16-14.43.33:855][258]LogNet: InitBase PendingNetDriver (NetDriverDefinition GameNetDriver) using replication model Generic
[2025.06.16-14.43.33:858][258]LogInit: WinSock: Socket queue. Rx: 32768 (config 32768) Tx: 32768 (config 32768)
[2025.06.16-14.43.33:858][258]LogNet: Created socket for bind address: 0.0.0.0:0
[2025.06.16-14.43.33:859][258]LogNet: IpConnection_2147482355 setting maximum channels to: 32767
[2025.06.16-14.43.33:859][258]PacketHandlerLog: Loaded PacketHandler component: Engine.EngineHandlerComponentFactory (StatelessConnectHandlerComponent)
[2025.06.16-14.43.33:860][258]LogHandshake: Stateless Handshake: NetDriverDefinition ‘GameNetDriver’ CachedClientID: 7
[2025.06.16-14.43.33:860][258]LogNet: Game client on port 7777, rate 100000
[2025.06.16-14.43.33:860][258]LogNetVersion: ProjectHorror 1.0.0.0, NetCL: 43139311, EngineNetworkVersion: 42, GameNetworkVersion: 0 (Checksum: 174104283)
[2025.06.16-14.43.33:863][258]LogSockets: Warning: GetAddressInfo failed to resolve host with error SE_HOST_NOT_FOUND [11001]
[2025.06.16-14.43.33:865][259]LogNet: Warning: Encountered an error, cleaning up this connection now
[2025.06.16-14.43.33:872][260]LogNet: Error: UEngine::BroadcastNetworkFailure: FailureType = PendingConnectionFailure, ErrorString = Your connection to the host has been lost., Driver = Name:PendingNetDriver Def:GameNetDriver IpNetDriver_2147482418
[2025.06.16-14.43.33:872][260]LogNet: Warning: Network Failure: PendingNetDriver[PendingConnectionFailure]: Your connection to the host has been lost.
[2025.06.16-14.43.33:872][260]LogNet: NetworkFailure: PendingConnectionFailure, Error: ‘Your connection to the host has been lost.’
[2025.06.16-14.43.33:872][260]LogNet: DestroyNamedNetDriver: Name:PendingNetDriver Def:GameNetDriver IpNetDriver_2147482418
[2025.06.16-14.43.33:884][261]LogGlobalStatus: UEngine::Browse Started Browse: “/Game/Maps/MainMenu?closed”
[2025.06.16-14.43.33:884][261]LogNet: Browse: /Game/Maps/MainMenu?closed
[2025.06.16-14.43.33:884][261]LogNet: Connection failed; returning to Entry
[2025.06.16-14.43.33:884][261]LogLoad: LoadMap: /Game/Maps/MainMenu?closed

Steam
[2025.06.16-13.33.35:635][803]LogGlobalStatus: UEngine::Browse Started Browse: “steam.76561198968469460/Game/Maps/MainMenu”
[2025.06.16-13.33.35:635][803]LogNet: Browse: steam.76561198968469460/Game/Maps/MainMenu
[2025.06.16-13.33.35:635][803]LogNet: InitBase PendingNetDriver (NetDriverDefinition GameNetDriver) using replication model Generic
[2025.06.16-13.33.35:637][803]LogInit: WinSock: Socket queue. Rx: 32768 (config 32768) Tx: 32768 (config 32768)
[2025.06.16-13.33.35:637][803]LogNet: Created socket for bind address: 0.0.0.0:0
[2025.06.16-13.33.35:637][803]LogNet: IpConnection_2147482228 setting maximum channels to: 32767
[2025.06.16-13.33.35:638][803]PacketHandlerLog: Loaded PacketHandler component: Engine.EngineHandlerComponentFactory (StatelessConnectHandlerComponent)
[2025.06.16-13.33.35:638][803]LogHandshake: Stateless Handshake: NetDriverDefinition ‘GameNetDriver’ CachedClientID: 2
[2025.06.16-13.33.35:638][803]LogNet: Game client on port 7777, rate 100000
[2025.06.16-13.33.35:638][803]LogSockets: Warning: GetAddressInfo failed to resolve host with error SE_HOST_NOT_FOUND [11001]

2

How are you testing?

FYI, Server and Clients need to use different accounts.

3

The build is pushed to Steam, my friends and I downloaded it and tested on our own individual accounts, which are all added to Steamworks. We are located in the same city. In version 5.5, everything works fine with the same setup. However, in version 5.6, even a clean project with just the multiplayer setup doesn’t work. The dedicated server seems to function properly — the problem persists only with listen servers, according to discussions in the Unreal Discord.

Again, session creation works fine, and traveling to the level as the server also works correctly. Clients can find and see the sessions, but they cannot join — error logs were included in my previous message.

4

Hello!

I solved it by adding SteamSockets plugin and dependency.

Then i just updated my DefaultEngine.ini

[/Script/Engine.GameEngine]
!NetDriverDefinitions=ClearArray
+NetDriverDefinitions=(DefName="GameNetDriver",DriverClassName="/Script/SteamSockets.SteamSocketsNetDriver",DriverClassNameFallback="/Script/SteamSockets.SteamNetSocketsNetDriver")

[OnlineSubsystem]
DefaultPlatformService=Steam

[OnlineSubsystemSteam]
bEnabled=true
SteamDevAppId=480
bInitServerOnClient=true

[/Script/OnlineSubsystemSteam.SteamNetDriver]
NetConnectionClassName="OnlineSubsystemSteam.SteamNetConnection"

Notice the actual netDriverDefinitions.

5

Aahhh, thought you would have already had that implemented.

I need to do a guide.