Error:
Error 21916724:
Short Message: Invalid compatibility combination(s).
Long Message>One or more compatibility combinations are invalid. Name, value, or name-value pair are not recognized.
Explanation:
This is only a warning, which would not prevent you from listing new items or from updating already active listings and eBay would return it, because there are some compatibility combinations in the sent fitment data, that eBay would consider as invalid according to what they have in their catalogue and they would be dropped off.
Resolution:
Go to the Logs page (left-hand navigation). Under Channels, select ebay to filter by that channel, then use the + Add filter by control to add an identifier filter and enter the item's guid. The matching log rows will show the related history for that item; the invalid compatibility combinations will appear in the entry that shows warning in the result/warnings column, since it contains the most detailed information the channel returned for that item.