Relist Items: Success
ebayid:82 Failure | ErrorCode:21916635
ShortMessage:Invalid Multi-SKU item id.
LongMessage:Invalid Multi-SKU item id supplied with variations.
Problem: You are getting this error because the original item was not a Multi-SKU item and you are trying to relist it as a Multi-SKU item.
If the original item was not listed as a Multi-SKU item, you cannot change it to be a Multi-SKU item during relist (or revise). You will need to create a new listing as a Multi-SKU item.
Solution: You have to export and relist the whole variation