To fix this issue, please try the following steps:

1. Download the latest version of the soundcore app from your App Store (if you already have the soundcore app, it is recommended to uninstall it and then download it again, overwriting installation is not recommended).

2. Pair your earbuds with your phone. Currently, the soundcore app does not support computers.

3. Open the app, and click "Add Device" on the left page, the app will automatically connect to soundcore Sport X20 (the first time you enter the app, you must agree to enable location permissions).

4. If the connection fails, click Set up Manually > Other Series > soundcore Sport X20 to check whether it can be added manually (if you can't find the corresponding model on this page, you can take a screenshot).

5. Go into the region of the system, switch to English (United States), and switch the system language to English (United States).

6. If it still fails, please uninstall and reinstall the app and log in again.

If you're still unable to connect after following the provided steps, please send the model of your mobile phone, the app version, and screenshots of the issue to our customer service team.

First connection successful, subsequent connections unsuccessful:

1. Check if it's in Dual-Connections mode, if the user has connected to the app on phone A, it will not be possible to connect to the app on phone B. You can try exiting the app on phone A.

2. Restart the device, or try using a different device.