This error is coming from Amazon. Your account has been blocked and is not permitting us access. You are likely getting a lengthy error message, something like this - but specific to your MerchantID (where the XXXXX is below):
Amazon message: encryptedMerchantCustomerId: XXXXX is unable to inbound. Reason: Seller is blocked by the AndonCordManager. - This operation may be partially successful, Please check the status. Reason: encryptedMerchantCustomerId: XXXXX is unable to inbound. Reason: Seller is blocked by the AndonCordManager.Request Id: YYYYYY
Issues can focus on physical and functional defects or inconsistency with the product page description. For instance, the physical item lacks a feature that was listed on the product page or its coloring is different.
If the above does not resolve this, you will need to contact Seller Central support and give them the text of the error message you are getting.