Modifying 1st Line of an Http Request

Hello I am working with a Product Called Dell Boomi, an iPAAS. Integration Platform where the HTTP connector adds “null” to the end of the GET line, 1st line
GET /v2/groups HTTP/1.1: null
GET /v2/groups HTTP/1.1

Postman works, Boomi getes a 401 error, . Its quite a high security Server regarding encryption and I think the null is causing 401. So the question is: is there a way to add in this “null” in say a pre-request script t either prove or disprove. I dont mind beig wrong. Thanks