Welcome to the Candy Crush Saga Community
Do you have a question or need help with your game? Ask the Community.
If you use the search function you will probably find a few things that will help you out.
I found this thread which has 2 suggestions for you:
https://care.king.com/en/candy-crush-saga/i-cannot-play-on-my-iphone-it-shuts-right-off