1. From the Shipped orders tab, use the Columns button to display both the Channel Status and Marked Shipped columns.

2. Filter orders by the desired date range, then look under the Channel Status column for orders with "Unshipped" status and a cancelled icon under the Marked Shipped column. You may also see orders tagged with "Failed mark as shipped" and can use this as a filter if you wish.

3. From there, you can then choose to resubmit manual mark as shipped requests manually or in bulk.