Error Code 8040
This is the brand restriction error. The reason for this error is that you can’t create a new variation relationship for this particular brand because it needs authorization from the Brand owner. Products that you are listing can be published only within the Brand’s control.
You will need to submit a Helpdesk ticket to Amazon who will reply with detailed information about the error. Alternatively, you can add offers to already existing ASIN for this brand. (Fast Listing)