1) This error may occur when there are inconsistencies on the product detail page. For example, the color scheme conflicts with the product page.
2) Check your shipments in the service overview "Overview - Incoming stock problems".
Maybe that's where the problem is (for example, sending in an overweight carton) that you need to confirm on the summary page or the shipping page so that you can then be cleared to send in again.
3) If nothing is listed here, try to make a submission via the ASIN in stock. If you experience similar issues, contact seller support.
Once the issue is resolved and Amazon deletes this bug from the MWS API, you will be able to submit again.