We are ready to answer any questions you have.
Enpass allows you to link your purchase with an email ID, which helps you to restore purchase across multiple devices.
When you see this error, it means you have already linked your existing purchase to a different email ID earlier; mentioned in the prompt.
Use the same email to activate the subscription license on the device, and you can later change the email by following the steps mentioned here. Write to us at support@enpass.io if you face any issues.