iMessage
I recently sent a large message to someone and my iMessage just broke. Whenever I try to turn it on it’s just a black screen. I’ve tried turning on and off messages, shutting down my iPhone, and force restarting it.
Welcome to the Apple Support Communities.
Make sure iOS is up-to-date: Update iOS on iPhone - Apple Support.
If it is, and you still see this, see: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support.
Jack