White noise and muffed sound microphone. iMessage only

Thanks for posting in the Apple Support Community maxime267,

If you're encountering issues with sound on your iPhone, the following apply specifically to this type of behavior and may provide a solution:

Follow these steps

1: If your device has a Ring/Silent switch, move the switch forward—toward the device's display—so that orange isn't showing. If you're using an iPad, you can also swipe down from the top-right corner to open Control Center and make sure that Silent Mode is off. 

2: Open Settings > Focus > Do Not Disturb and make sure that Do Not Disturb is off.

Contact Apple Support

If you checked the sound settings and your device still has sound issues, contact Apple Support to discuss service options.

If you want to try more steps on your own

If you prefer, here are some more steps you can try on your own. After following these steps, you might still need to contact Apple Support to discuss service options.

1: Remove all screen protectors, films, or cases from your device. 

2: Check the speaker opening to see if it's blocked or dirty. On iPhone only, make sure that the receiver isn't blocked or dirty. 

3: If necessary, clean the speaker or receiver opening with a small, soft-bristled brush. Make sure that the brush is clean and dry.

4: Go to Settings > Sounds (or Settings > Sounds & Haptics), and drag the Ringer and Alerts slider back and forth a few times. If you don't hear any sound, or if your speaker button on the Ringer and Alerts slider is dimmed, your speaker might need service.

5: If you hear sound, try making a call with your iPhone and turn on speakerphone. On iPad or iPod touch, make a FaceTime call. If you still can't hear, or hear static or crackling, then your network or reception could be the issue. Try to call again later, or from a different location.

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker

We hope this helps!