Multiplayer Blueprint proplem,PLEASE HELP ME,IM IN THE MIDDLE OF A PROJECT

Hello can i get some help over here please guys,i swear ive done everything in this tutorial Blueprint Multiplayer: Lobby Game Mode | 15 | v4.11 Tutorial Series | Unreal Engine - YouTube
everything works great and following it, till the 15th tut
everything works fine but the start session button is grey and i cant press it so i can go to the Arena01 any help? i done everything in tuts
i hope some of you are familiar with this tut series
i can provide pictures of the “Start Session” button blueprint


Please review this thread: "Blueprint Multiplayer" Video Series is teaching a lot of wrong things - Documentation Feedback - Unreal Engine Forums

This might provide some insights…