The message itself is a Android error message. The head unit is essentially an Android device. This particular message means that the app called "SmartPhoneConnectUtils" has crashed, so Android had to stop it. You can probably clear it by turning the car off, and on again. That should re-start Android, but won't do anything about what caused the crash.
And in my experience with "Power Flow" (it's happened twice) and "Tunner" (not to me, but it affects the FM, and we seemed to think it was a mispelling unless they are brewing beer in the car), rebooting wasn't necessary. The app has to initialize, not the Android system. But, as always, your mileage may vary.Unfortunately, restarting the car may not work because that doesn't really reboot the head unit. Try this: