If you have an SP-API application that is not published but the OAuth workflow points to Production workflow, this error is returned. To resolve, please contact us at firstname.lastname@example.org and be sure to lets us know:
1) Your account name, marketplace, and if possible the entity ID
Once we have this information we can send it over to our tech team and they can get to work correcting the issue.
We look forward to speaking to you soon!