What's the matter with the ringtone of iphone 12 automatically decreasing?

The sound of Apple's mobile phone suddenly becomes low, which is caused by the following reasons: Press the volume adjustment button on the side of the screen to adjust the volume when talking. If not, try to see if the sound is the same as that on the earphone. 2. Turn off "Call Noise Cancellation" in Settings-General-Accessibility. You can try to turn off the phone, clean the dust on the receiver, and then turn it on to set the volume. 4. Back up mobile phone data (phone book, text messages, pictures, etc. ) and restore the phone to the factory settings. If you are uneasy about the fourth method or afraid of problems, I suggest you go to the repair shop, or there may be something wrong with the original mobile phone.