Sometimes my iPhone gets wonky with the Toyota/Lexus BT cars. My 2015 Prius, 2016 CT200h, and now IS200t. Occasionally theres no BT connection and i have to shut off the engine and restart to get it to connect. All three of those cars. Toggling the stereo on/off, bt on/off, airplane mode etc doesn't work. Rare but it happens.

 

For the IS, you can restart the entire audio system in the car by holding and pressing down the power **** for a few seconds. This should reset it so the bluetooth works again without turning off/on your entire car. Not sure if the Prius and CT have a similar method.