Crashes upon opening on mobile

hi

Ive purchased this app for my son - he loves it..but lately upon opening it crashes and after a black screen just returns to the homescreen

 

This is a bit frustrting seen Ive paid for this game..and now it doesnt function

 

He plays it on his Sasmung Galaxy J phone

 

It was running great..no issues..but now this

 

Ive got no idea as the the workings of these things

 

Please assist asap!! hes making me mad!!

 

Regards