The error for FBA_INBOUND_CARTON_016 indicates that you have more items in your Seller Central Working Shipment than you do in your Stratify Box Content Information.
This can happen if you have changed the quantity of items in the Working Shipment in Seller Central, but have not yet made the same actions within the Stratify Box Content section.
Note: With the Send to Amazon workflow, you can only follow the steps below prior to navigating to the shipment's page in Seller Central. Once you are on the shipment page with Send to Amazon, changes can no longer be made through their API.
If corrections need to be made in Stratify, navigate to the List>List & Prep page and locate the shipment in the Working Shipments area.
Click the 3 horizontal lines next to it, then select Work on Shipment.
Make sure the quantities of your items in Seller Central match the quantities of the items you have assigned to boxes in Stratify.
Note: You would assign a quantity of 0 or click the trash can icon next to an item in Stratify if you have deleted it from your shipment completely in Seller Central.
For additional steps to help with editing the quantity of items in the shipment or adjusting box assignments, please see- Editing Box Level Content Information
Once everything looks correct, click the Transmit Updated Boxes button in the lower right-hand corner.
Wait for the green Success message on the right-hand side of the page.