Overview

Amazon error 18865 appears when a vendor tries to enroll an ASIN that is already linked to a different vendor code within the same marketplace. The system blocks the second enrollment, forcing the seller to work with Amazon vendor support to clear the conflict. Prompt resolution is essential because the blockage can halt catalog updates, purchase orders, and revenue flow.

Key Points

• One‑vendor‑per‑ASIN rule — Amazon permits only a single vendor code to hold an enrollment for a given ASIN in a marketplace, so any duplicate attempt is automatically rejected.
• Typical trigger — The error most often shows up when Vendor A attempts to register an ASIN that Vendor B has already enrolled, whether the two vendors are separate companies or different accounts owned by the same organization.
• Support‑only fix — Unlike many self‑service alerts, error 18865 cannot be cleared through the Seller Central UI; it requires a case opened with Amazon’s vendor support team.
• Documentation requirement — Amazon asks for contracts, distribution rights, or authorization letters that prove the requesting vendor’s legitimate claim to the product.
• Internal account overlap — Companies that maintain several vendor accounts may unintentionally create competing enrollments, leading to the same error across multiple ASINs.

How the Conflict Detection Works

1. Enrollment request submission — A vendor enters an ASIN into the enrollment screen and clicks “Submit.” Example: Vendor X tries to add ASIN B07XYZ1234 to the “Subscribe & Save” program.
2. System lookup for existing vendor code — Amazon’s backend searches the marketplace database for any active enrollment tied to that ASIN. Example: The lookup finds that Vendor Y already has the ASIN enrolled under vendor code V12345.
3. Duplicate‑code comparison — If the found vendor code differs from the one submitting the request, the platform flags the transaction as a conflict. Example: Because V12345 ≠ V67890 (Vendor X’s code), the system generates error 18865.