Game don't work on Mobile

In advance I apologie for my bad english, still learning.

 I made an app with only blueprint. I know it's not ideal to made an app in ue4 (And with blueprint), but at the moment is what I can do, my objective is to learn more about blueprint and UE4 in general, and help my class pass in an exam. the app contains one blank map and an UI blueprint, everythings work well on pc but not on mobile (Android-Mi 9T Pro). On mobile it stops working on launch, at times it opens (1 in 10) but at some point it stops working. I have a Log that ponts "null pointer dereference" but I really don't understand what it is, have tried everything in the package section and none works. 

My questions is, is it possibly that the app is to demanding to mobile? That error "null pointer dereference" (screenshot bellow) could means it? 

Is it a problem to use only one Widget to the entire app? Is it too demanding? Should I use more widgets? Should I Nativize? (Tried that but it didn't work, some error at the nativization process, but I didn't tried much)

Please help, I'm trying to solve this problem for an entire week and nothing works, I'm desperate :""(

Hello, well there could be many things that could go wrong. Does it launch on your mobile? Have you checked build to ES 2.0? I made an application myself in ue4 with only using widgets so I don’t think that problem is widgets. Could you tell little more info about the project what you already tried…

Thank you for your reply Panteplak.

It launch sometimes, and works well.

I don’t have an Suport OpenGL ES2 option, guess it is removed on 4.25.