How to fix iPhone 7 can’t hear callers, callers can’t hear (microphone stops working) issues

The best option to solve this problem is to factory reset

Because a master reset or factory reset wipes your iPhone's media files, data, and settings, making a backup of your device's contents is highly recommended. Standard techniques for doing a factory reset on the iPhone 7 smartphone are outlined below:

1. To get started, go to the Home screen and select Settings.
2. From the Settings menu, scroll down to General and hit it.
3. After that, scroll all the way down to the bottom of the screen and tap Reset.
4. Erase All Content and Settings is the option to choose.
5. To continue, tap Erase iPhone.
6. Tap Erase iPhone one more to confirm the process.
7. Enter your Apple ID password if required, then press Erase.
8. Wait for your iPhone to finish the reset process, and then your device should be as good as new.
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