Please try the following troubleshooting steps：
- Please use the phone's built-in recording function to confirm whether the sound can be recorded.
- Do not use other APP operations to prevent setting the earbuds microphone to be disabled.
- If you answer a call, you need to set the default answering device as "earbuds".
Please try the following troubleshooting steps as these have proven to help:
- Use the default phone call on another phone to see if it makes any difference.
- Reset the earbuds as shown below to see if the problem persists.
- Place the earbuds in the charging case and make sure they are charging.
- Keep the earbuds inside the charging case and hold the button on both earbuds for 3 seconds. The LED indicators will flash red 3 times and then turn white.
1. Make sure the earphones are fitted correctly and have a good seal.
2. If using a calling app, try making a call from your phone to see if that resolves the issue.
3. Connect other devices to see if the playback is normal in different environments.
1. If you are only using one earbud, make sure the other earbud is in the charging case.
2. Choose the eartip (including the other eartips included) that best fits your ear size and make sure it provides a good seal.
3. Confirm that the audio output of the connected device is set to "QCY T13" and turn up the volume of the device.
4. If using a calling app, try making a call from your phone to see if that resolves the issue.
5. Connect another device to see if it plays normally in different environments.
We suggest trying the following:
- If you only use one earbud, make sure the other earbud is in the charging case.
- Try different sizes of ear tips that come with the earbuds and make sure you're wearing them in the correct position to create a tight seal.
- Please make sure the audio output device chosen is "QCY T13" on the connected device.
- If you make a call via an app, please try using your phone to make a call and see if the problem still persists.
- Try testing your earbuds with a different Bluetooth device in a different environment to see if it makes any difference.