Certification with vantiv, throwing exception

I am new to vantiv, as a developer I wanna certify the MX925 device and display sample text like "Hello World".

I try to fire Postman GET with ApplicationID,Token, ID, acceptor ID values from email when i registered.

https://triposcert.vantiv.com/api/v1

But response is 500 Internal server error with JSON as follows:

{

  "exceptionType": "TriPos.Shared.Exceptions.InvalidRequestException",

  "exceptionMessage": "The request header is missing [tp-application-name]."

}

Could you help me where I am missing whether I need to send any forms to get certify or is the issue is with public/private keys?

Thanks again in advance.