Why is there still external sound after connecting the Redmi Buds 6 Play to the mobile phone?

The earbuds and phone are connected, but music, videos, calls, and other sounds are still being played externally.
The reasons for the problem are as follows:
Bluetooth is connected, but the [Media audio] option is not selected.
To resolve the above problem, please refer to the following methods:
1. After connecting the earbuds to the phone, go to [Settings] >> [Bluetooth] >> select [Redmi Buds 6 Play] >> enable [Media audio];
2. On the Bluetooth settings of the phone, disconnect Bluetooth and reconnect Bluetooth;
3. Turn off Bluetooth on the phone, turn on Bluetooth again, and the earbuds and phone will automatically reconnect successfully.
If none of the above can solve the problem, please try restoring the factory settings. Press and hold the button for 10 seconds, and the indicator will flash. Reconnect to restore the factory settings.