Ios 15.0.2 bug

It might be a temporary glitch.

I suggest that you try a "forced" restart of your iPhone, using these instructions:--> Force restart iPhone – Apple Support

If the issue persists, make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector. After checking it out, they'll give you all the available options.

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.

• Restart the device. That's it.
• Still not solved --> Force restart iPhone - Apple Support

Force restart immediately, should do the trick