When processing orders you might come across the "Hard 120020 - Max packages per shipment exceeded" error.
This error is shown when the amount of packages in your order exceeds the maximum amount allowed by the carrier per order.
Feel free to follow the step-by-step guide written below or the video guide, as you prefer:
To correc the issue:
1. Find the order through any of the possible ways (after Import Orders, Batches, Order History, etc) as it applies to the case
2. Click the edit button of the order you wish to change
3. Select the Packaging tab
4. Remove packages to meet the carrier's requirements (25 max per order - How many packages can be added into FedEx Ship Manager at fedex.com?)
5. Press Save to apply the changes
If the rest of the information in the order is correct, you will be able to process it.