1. Check whether the speaker is blocked or blocked (such as the influence of protective sleeve/shell or film) and clean it with a soft brush.

2. Restart the phone to see if it is restored.

You can pull down the status bar of your mobile phone and try to set it to ring.

4. Check whether the speakerphone volume is normal, confirm whether it is a video or player problem, and eliminate abnormal resources such as video and music.

5. If there is unilateral mute or low sound after adjusting audio equalization, you can enter "Settings >"; Other settings > accessibility > audio equalization ",pull the audio adjustment point back to the middle, restore to the default position, and then return to normal.

ColorOS 12 system mobile phone setting path: "System Settings >; Accessibility > hearing >; Balance the volume of the left and right channels and pull the audio adjustment point back to the middle.

If it is a hardware problem or the above methods can't solve your problem, it is recommended that you back up important data in advance, take your mobile phone and purchase certificate to the OPPO customer service center for testing, and professional engineers will solve it for you.