Error Code 21916750 “You are not allowed to revise an ended item”
You receive this error when you try to revise a listing on eBay that has ended. If you are sending a product update, this will not work for items that have ended. You cannot revise an ended item if you are sending product data update.
Try to relist the issued product.
1- Select the product and send the “Delete and Recreate” feed to eBay.
2- Sync the channel.
You can also use the article below to understand the relisting on eBay.