Variation specifics mismatch with active listing

Error 21916664 fires when you try to revise a multi-variation listing and the variation specifics don't match what's already published. eBay locks variation structure after the listing receives a sale.

You changed the variation axis (e.g., switched 'Size' to 'Length'), reordered variation specifics, or added a new variation specific that wasn't in the original listing. Once a listing has bids or sales, the variation structure is partially locked.

1. Compare the new variation specifics to the active listing's set - they must match exactly.
2. If you need to change the variation axis, end the listing and create a new one.
3. Add new variations only - don't reorder or remove existing ones with sales.
4. For variants without sales, you can still remove them via revise.
5. Resubmit only after the variation structure aligns.

• Reordering variation specifics in the source feed and pushing as a revise
• Renaming 'Color' to 'Colour' on UK listings without ending the listing first