My survival world is stuck in single player

My survival world is stuck in single player. I have started from having a survival, then I moved into a new home and the world disappeared from the menu. I signed up for the beta testing program and it appeared again, then I had used the features in the world and signed off of the beta program. My world could not work until 1.9, where it could be accessed but it would not allow multiplayer. What should I do?

 

-Derred

P.S. In the future I'll try to attach a screenshot