The factors about one earbud having no sound are as follows:
1. Poor contact with one earbud causing Bluetooth pairing to only recognize one side;
2. Low battery causing the earbud to shut down;
3. Blockage in the earbud sound outlet;
4. Potential water or sweat damage leading to short-circuit or malfunction.
To resolve this issue, please refer to the followings:
1. Place the earbuds back into the charging case to ensure the charging case indicator lights up when they are inserted, then re-pair via Bluetooth;
2. If due to low battery, ensure the earbuds have good contact, charge them in the case for 10 minutes, then re-pair via Bluetooth;
3. Check and clean any debris from the earbud sound outlet;
4. Reset the earbuds by placing them in the charging case, opening the case, and pressing the bottom button of the charging case for 10 seconds until the indicator lights up, which clears the pairing records. Then proceed to re-pair the earbuds.
If issues persist, consider contacting the local after-sales service center for further assistance.