Returned status in NTSA TIMS portal when accepting ownership means that your application has been reverted back to the owner to rectify details or provide more documents.
In most cases, the cause of this problem is the Logbook. Confirm whether the Logbook is jointly owned. Also ensure that you have uploaded all documents pertaining the vehicle.
You can click on the VIEW button to see the reason the why the application was declined.
If there are no reasons, then visit NTSA Offices to have your details updated.