The attributes are invalid

item_type_name: The attributes are invalid.

The item type field is an example. This error message might show up for different fields.

This error indicates that entered data in the Creation profile are not accepted by Amazon. It might happen when you enter the value that is not supported by Amazon. For example, the variation name from the Shopify store is "XL" whereas Amazon accepts "X-Large" value. Check this article on how to resolve the issue with variation naming between Shopify and Amazon.

Another case when this error shows up is when you use the Creation profile that you added some time before. From time to time, Amazon updates available attributes for various product types. If this attribute is no longer relevant on Amazon but an added field exists in the mapping in the Creation profile, such an error might show up. The solution here is to create a new mapping (or new Creation profile) and use a new one instead of the old one.