Aktiia device is meant for personal use only and should not be shared.
The error message is displayed when you try to pair an Aktiia device to two different user accounts.
One account = Aktiia Bracelet + Aktiia Cuff
Ensure that only the Aktiia Bracelet you are trying to pair is on the charger and/or the Aktiia cuff you are trying to pair is the one that is paired with your account.
Please see the following FAQ`s for further information on how to pair/unpair your Aktiia devices: