How do I address the following error on a Solicitation Response: “A response was previously submitted for this Vendor's TIN (A3596)”?

This Solicitation Response error:

Screenshot of error code: A response was previously submitted for this Vendor's TIN

is the result of selecting the "Restrict Multiple Responses per Vendor TIN" (optional) entry on a Solicitation, then creating two or more Solicitation Responses using Vendors that share a TIN (Tax Identification Number).

A screenshot of Restrict Multiple Response per Vendor TIN field with the box checked.

The only way to address this error once a Solicitation with this selected has closed is to coordinate an override with the CORE Help Desk. The proactive way to address the problem is to not select the “Restrict Multiple Responses per Vendor TIN” checkbox on your Solicitation before publishing it.