Why are the camera buttons gray when Apple sends text messages?

1. Apple sent a text message, and the discharge was not due to the theme of the mobile phone. Generally speaking, the whole interface is gray, so it is normal to say that the camera buttons are gray. Click to use it normally.

2. Another point is that the gray color of the camera keys is lighter than others, so you can't click to use them, which means you don't have the function of sending and receiving MMS. You need to turn on the function of sending and receiving MMS in the phone settings before you can use the camera key.