Why can't I pair Ear (open) to my iPhone after reset?

1. Open Settings on your iPhone.
2. Tap on Bluetooth.
3. Find the earphones you want to delete.
4. Tap the 'i' icon next to the earphones.
5. Tap Forget This Device.
6. Confirm the action by tapping Forget Device in the pop-up.
7. Open the Nothing X App to pair the earphones again.