Error: No Connected Inbox for User Email in Public API Enrollment Request

"status": "error", "message": "User 80311826 for Portal 7698645 has no connected inboxes for specified user email, which are required in order to enroll from the public API.", "correlationId": "018b81d5-2b71-476d-a860-77b9b5fef7df", "context": { "userId": [ "80311826" ], "portalId": [ "7698645" ] }, "category": "BAD_REQUEST", "subCategory": "SequenceStandardFriendlyError.PUBLIC_ENROLL_NO_CONNECTED_EMAILS" }