Can't Join to Session Steam

I’m trying to connect via Steam (not Lan). My friend creates a session (“CreateSession”). I’m looking for server (“FindSession”) and find my friend. I can recognize this because I run the GameServerName into a PrintString. The PrintString shows the friend’s name. Now I try to join (JoinSession), but nothing happens. We start the game of Package. I use the “listen” option for “OpenLevel” for CreateSession.
Why can not I join?
I Use BluePrints

I need this Settings in DefaultEngine.ini. I think only the port is what i need. Its work.

[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

I have the same problem, your solution was not helpful…

I got the same problem, tried everything still can’t find answer

WriteAndFight,
Are you saying that you can find the session with your client but cannot join? I have this working on a couple of blueprint projects so maybe I can help if I can understand your problem exactly.
First things I would say though is
you do have these lines in defaultengine.ini:-
[/Script/Engine.GameEngine]
+NetDriverDefinitions=(DefName=“GameNetDriver”,DriverClassName=“OnlineSubsystemSteam.SteamNetDriver”,DriverClassNameFallback=“OnlineSubsystemUtils.IpNetDriver”)

[OnlineSubsystem]
DefaultPlatformService=Steam

[OnlineSubsystemSteam]
bEnabled=true
SteamDevAppId=480

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

And, you do have the steam online subsystem plugin enabled?

When you find a session what do you do with the session information that you have found?

do you print to screen messages to let you know what is happening?

If you post your host, find and join blueprints it might help.