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.
Solution:
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)