Host Session and Join Session Failing

Hi, I am trying to make my first multiplayer game. I have a feeling I am doing it wrong. I have it so when you press a button, it calls a function like host or join game. Whenever I press the button, it fails to function and shows the error message that I had implemented. How do I make these functions work as intended. I know the event is being called but just failing.Please help, Thanks! This is my blueprint:

Sorry, I am new to unreal, can you please dumb that down for me? Also, how do I do that?

Hey there, make sure you have the null subset system configured in the ini file.

In your DefaultEngine.ini you need to edit/add this:

[OnlineSubsystem]
DefaultPlatformService=Null

More information here.

ok thanks I will try that