Stop while playing and start to load

Hello

i have a problem that happened always 

i am playing the game on ios on ipad pro 

while playing stop the game suddenly and then started to load like in the photo that i sent 

i have been wait for this long time but not finished then i have to close the game and restart it. First i was playing for one hour and then stoped but now i can not paly because this problem happen every 5 minutes . So i need a solution.

thank you so much 

waiting for the reply 

sami rustom