If your phone's volume is lowering automatically when you open or close the phone, this may be due to a feature called "Attention Aware" that's built into iOS. When this feature is enabled, your iPhone can automatically lower the volume of your music or other media when it detects that you're looking away from the screen, such as when you're on a call or using Face ID to unlock your phone.
Here's how to disable this feature:
- Open the Settings app on your iPhone.
- Tap on "Face ID & Passcode" (or "Touch ID & Passcode" if your phone doesn't have Face ID).
- Enter your passcode.
- Scroll down to the section labeled "Attention Aware Features".
- Toggle off the switch next to "Attention Aware Features".
Once you've turned off this feature, your iPhone should no longer automatically lower the volume when you open or close the phone.