UE 5.1 Steam Sockets Problem

Hey all, I can’t get joining to work with Steam Sockets, and I’m pulling my hair out trying to figure out what’s going wrong. I’m on 5.3, with no Advanced Sessions plugin. When I try to join a LAN game with steam sockets, I just get kicked back to the menu. This is the log. I can join LAN games with steam disabled though…

What am I doing wrong :face_holding_back_tears:

(Ignore FCTween warning, not relevant.)

DefaultEngine.ini

[URL]
GameName=<REDACTED>
Port=27015
PeerPort=27015
QueryPort=27015

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

[OnlineSubsystem]
DefaultPlatformService=Steam
PollingIntervalInMs=20

[OnlineSubsystemSteam]
bEnabled=true
bUsesPresence=true
bRelaunchInSteam=false
bInitServerOnClient=true
bUseLobbiesIfAvailable=true
SteamDevAppId=<REDACTED>
bUseSteamNetworking=true
bAllowP2PPacketRelay=true
GameServerQueryPort=27015
P2PConnectionTimeout=90

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

[Core.Log]
LogOnline=VeryVerbose

[SystemSettings]
net.CurrentHandshakeVersion=2
net.MinHandshakeVersion=2
net.VerifyNetSessionID=0
net.VerifyNetClientID=0