79 (Invalid Participant Identification) Error

Eligibility v3 API throws the 79 (Invalid Participant Identification) error when the CMSMED is passed as the tradingPartnerServiceId.

CMSMED requires NPI enrollment before they reply to your requests. Have you enrolled any NPIs you are using in the request with CMS through the ConnectCenter and Enrollments Central?
If you are still in implementation, you can contact [email protected] for more detailed help.