When the IPHONE sends a text message, the program will automatically quit. And there is often no signal.

Maybe it's a memory problem You double-click HOME, press a program at will, and delete all used programs, that is, you quit completely. Try again. Because there are too many open programs, I temporarily quit my memory. I sometimes quit playing games automatically. I suspect it's a memory problem. Give it a try and hope to solve our two problems successfully.