bluetooth headset with super bass Air31 Wireless Bluetooth 5.3 In Ear Transparent Earphones

describeBluetooth version: Bluetooth 5.3Transmission range: 15mMusic time: approximately 7 hoursCall time: approximately 4 hoursTotal working time: approximately 25 hoursRechargeable case battery: can charge the earphones 4 timesHeadphone charging time: approximately 1 hourCharging time for the charging case: approximately 1.5 hoursEarphone size: approximately 14.1x9.5x3.5cmSingle earphone weight: approximately 11gOverall size: approximately 57.5x47.5x19cmOne Bluetooth earphone is not working1. Check if the set mono output can be adjusted to two ear channels.2. Check if the battery of a headphone is depleted3. Check if the two headphones are connected to both devices. You can close the connection and remove the Bluetooth earphones from your phone's Bluetooth list.Pair your phone again and then play the audio againOne Bluetooth earphone is not working1. Bluetooth earphones are left for too long. If not used for a long time, the lithium battery inside the earphones will be in a "sleep" state. As long as the charging time exceeds 30 minutes, the earphones will display the charging status2. The earphones haven't been used for that long, and they don't show up even after charging for over half an hour. Check if the headphone charging cable plug is damaged. You can try other data cables or check if anything is blocking the charging point of the headphone. If available, please clean with a toothpick