Both bluetooth and CarPlay have been giving me a little bit of trouble with my iPhone 7 plus. I was playing music via bluetooth yesterday for few seconds and then all audio cut out. I looked at the phone and it was showing the song as still playing. If I turned BT off and then back on, it would pair the phone and pay a few seconds of music again and stop. Then I tried CarPlay and it wasn't recognizing a connection. I restarted the phone and tried BT again, only for the same result - it would play a few seconds then lose connection. After the restart CarPlay has been working normally. I also tried rebooting my car's audio system which didn't work.
I don't know if the bluetooth & CarPlay issues are related, but it's worth noting. I will try delete my iPhone profile from the car and re-pair when I get out of work and see if that solves anything.