Overnight, messages to one person who I message daily now is only SMS. My iMessage works to other iPhone users and I know someone else who texts him is using iMessage. His messages to me are SMS. I turned off SMS and it still uses SMS. I have done everything short of restoring my phone. Wifi is fine. Time is fine. Settings are fine. Resetting phone and network did nothing. He's too dumb to change settings snd says they are fine. What could have happened overnight? I'm using an iPhone 6 with version before the one with iWatch.