Error Code 21916884- missing item “condition”
When you list an item in some eBay categories, you must specify its condition. Conditions differ by item category, please check this eBay documentation to find out more: Item conditions by category and Item Condition IDs and Names.
Store Automator always uploads the 'new' condition as a default so you should not encounter this issue when uploading directly via Store Automator. If you still do, just specify the actual condition for each item.