Error:
Error Code: 21916580
Short Message: Values in name-value list exceed limit 30.
Long Message: Values per name-value list exceed limit 30 in variation specifics set container.
Short error: Values in name-value list exceed limit replaceable_value.
Long error: Values per name-value list exceed limit replaceable_value in variation specifics set container.
Explanation and resolution:
As the error outlined, the maximum amount of allowed variation fields like Size, Style and Color, that can be included and displayed as a single drop-down menu in the eBay listings are 30 and if the variation fields exceed it, then you would need to edit the items and reduce the particular variation fields to 30 or less and then resubmit the items to the channel.