Menu not working on Android.

I have been making a simple app on my phone for fun. It was working fine, and then i decided to make a menu so that you could pick what level of the game to go to. This has seemed to have broken the app I am making as the menu works fine, until it comes to the button to load the level (map) i want.

A picture is attached above of what I did for reference.

Does anyone know of any fixes etc?

Thanks in advance,