Error 21916293 fires when eBay's Listing Verification & Improvement Service blocks the listing as a policy violation. This covers prohibited, restricted, and suspect items.
Categories include: counterfeits, recalled products, non-FDA-approved supplements, hazardous materials, certain weapons, items that infringe IP, ivory/animal products, and some used cosmetics. eBay's automated classifier runs every listing through LVIS, and human review can follow.