AS3 json 422 error in VSTS

Working through the AS3 labs, I am using a similar json as what they have in one of the F5 labs. It creates a VIP and a pool. When I run it from postman it is successful and creates them in F5. However, when I try to use the same json and do the post in a VSTS pipeline I get a 422 error. Any ideas on what may be causing this?