Token Access

Hello,

I'm trying to get the token access through an html call, using the post, however in Postman, it works fine, however when I try to call inside the application the error.
What am I doing wrong.

Code

envelope="grant_type=password&scope=openid&resource=https://analysis.windows.net/powerbi/api&client_id=xxxxx&username=xxxx&password=xxxx&client_secret=xxxxx"

I'm using the object MSXML2.XMLHTTP60

            With xmlHTTP
                .open("post",  https://login.microsoftonline.com/common/oauth2/token, False)
                .send(Envelope)
                Retorno = .responseXML.xml
            End With

Error:

Ready State: 4

HTTP resquest status: 401