steam failed to bind to port 7777

I have my defaultengine.ini set per Rama’s tutorial…



[/Script/Engine.GameEngine]
!NetDriverDefinitions=ClearArray
+NetDriverDefinitions=(DefName="GameNetDriver",DriverClassName="/Script/OnlineSubsystemSteam.SteamNetDriver",DriverClassNameFallback="/Script/OnlineSubsystemUtils.IpNetDriver")
 
[OnlineSubsystem]
DefaultPlatformService=Steam
PollingIntervalInMs=20
 
[OnlineSubsystemSteam]
bEnabled=true
SteamDevAppId=480
GameServerQueryPort=27015
bRelaunchInSteam=false
GameVersion=1.0.0.0
bVACEnabled=1
bAllowP2PPacketRelay=true
P2PConnectionTimeout=90
 
[/Script/OnlineSubsystemSteam.SteamNetDriver]
NetConnectionClassName="/Script/OnlineSubsystemSteam.SteamNetConnection"


The DLL’s are already where they are supposed to be per the instructions. This is a NON C++ project, blueprint only.

Run the packaged program and shift tab brings up the steam overlay fine.

Try to create session, it fails with a netdriverlistenerror. Log:



[2015.09.20-02.44.45:576][276]LogNet:Warning: Failed to init net driver ListenURL: /Game/Maps/Abandoned?listen?game=DM: SteamSockets: binding to port 7777 failed (0)
[2015.09.20-02.44.45:576][276]LogNet:Warning: Network Failure: GameNetDriver[NetDriverListenFailure]: SteamSockets: binding to port 7777 failed (0)
[2015.09.20-02.44.45:576][276]LogNet: NetworkFailure: NetDriverListenFailure, Error: 'SteamSockets: binding to port 7777 failed (0)'
[2015.09.20-02.44.45:577][276]LogWorld: Failed to listen: SteamSockets: binding to port 7777 failed (0)
[2015.09.20-02.44.45:577][276]LogNet:Error: LoadMap: failed to Listen(/Game/Maps/Abandoned?listen?game=DM)
[2015.09.20-02.44.45:580][276]LogWorld: Bringing World /Game/Maps/Abandoned.Abandoned up for play (max tick rate 0) at 2015.09.19-19.44.45
[2015.09.20-02.44.45:580][276]LogWorld: Bringing up level for play took: 0.002452
[2015.09.20-02.44.45:581][276]LogOnline:Warning: STEAM: Can't start an online session (Game) in state InProgress



So it is failing to bind to port 7777. Checked windows firewall, nothing there bad. So what else can cause this?

I personally don’t know anything about this issue, but we’ll need to know a little bit more. Which tutorial are you following? Could you link it?

And running it from a packaged build, not the editor.

Nobody? …

With UE4.15 we had this bug.

Fix was in the DefaultEngine.ini
change
[/Script/Engine.Engine]
to
[/Script/Engine.GameEngine]