The very fast blinking earphone indicate that a factory reset is needed to have both earphones work as a pair again.
The "factory reset" is a way to have the earphones go back to the state they were in when leaving the factory. All data since then will be erased.
How the reset works:
- Put both earphones in the charging capsule. Press the capsule button with the lid open for about 15 seconds, until the capsule starts blinking in bright white light. The earphones will then blink very rapidly and settle down to blink in unison.
Please note that after a factory reset you need to:
- Remove all previously paired Earin A-3 in your list of Bluetooth devices.
- Press 3 seconds on the capsule button (earphones in capsule, lid open) and pair them in Bluetooth to your phone.
- iOS users need to delete the old A-3 product in the App under "Manage Products" and let the app connect to your earphones again.