Unable To Board a Merchant

We are trying to board a merchant using https://apitest.cybersource.com/boarding/v1/registrations but we always get a error: UNAUTHORIZED_USER response.

It works fine when we do it from CyberSource portal but fails when we try to replicate on Postman.

{
    "response": {
        "rmsg": "{\"error\":\"UNAUTHORIZED_USER\",\"error_description\":\"UNAUTHORIZED USER\"}"
    }
}

So we are probably missing the required authentication headers but the documentation page for it leads to 404: https://developer.cybersource.com/docs/cybs/en-us/payments/developer/all/rest/payments/GenerateHeader/jwtTokenAuthentication.html.

Our current header is:

- Authorization: Bearer <Bearer> 
 - Content-Type: application/json
 - v-c-merchant-id: alpha_001
 - Host: apitest.cybersource.com

Please let us know if we are missing any authentication headers in our request.

Start with the merchant-boarding registration endpoint and compare the Postman request with the request that succeeds in the CyberSource portal. Review the listed Authorization, Content-Type, v-c-merchant-id, and Host headers, then follow the referenced authentication documentation or its replacement. Done means identifying the missing or incorrect authentication detail and confirming a successful registration request.