How to log in with a post request to Microsoft Forefront TMG?

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Good afternoon everyone.
There was a following question.
There is a mobile application that must be authorized on a corporate server that uses Microsoft Forefront TMG. Actually, maybe someone knows what post request needs to be executed and what (and how) parameters to pass in the request?
Actually in Google Chrome I see the headers and the body of the request, I try to make a similar request through Postman, but it says that "There was an error connecting to https://mpr. "... After reading
some resources, they write that as a result of authorization, cookies should be returned...