POST/API Nonce Token with Gateway

Hi-

I'm trying to figure this out.

• I have an on-prem resource.
• I have a gateway that uses the Basic authentication method.
• I use the Basic authentication to get a NONCE token using GET. (this works)
• I then need to POST using this NONCE token to get the report contents for PowerBI. (this doesn't work in PowerBI but does work in python/POSTMAN)

The issue-

Web.Contents only wants to send POST requests using the anonymous authentication method. I see other examples online of people using custom powerquery however none seem to be going through a gateway. 

"An error occurred in the ‘ReportExecute’ query. DataSource.Error: Web.Contents with the Content option is only supported when connecting anonymously."

How do other users get reports into PowerBI from APIs that require a token and POST?

PowerQuery Code/Functions:

let
    GetCsrfToken = () as text =>
    let
        // HTTP Basic Authentication details (replace with actual username and password)
        AuthHeader = "Basic " & Binary.ToText(Text.ToBinary(Username & ":" & Password), BinaryEncoding.Base64),
        // URL
        BaseUrl = "https://INTERNALRESOURCE",
        CsrfTokenEndpoint = "/odataENDPOINTPATH/GetCSRFToken",
        TokenResponse = Web.Contents(
            BaseUrl,
            [
                RelativePath = CsrfTokenEndpoint,
                Headers = [Accept = "application/json", Authorization = AuthHeader]
            ]
        ),
        TokenJson = Json.Document(TokenResponse),
        CsrfToken = try TokenJson[NonceValue] otherwise error "CSRF token not found"
    in
        CsrfToken
in
    GetCsrfToken

let
    ExecuteReport = (ReportId as text, Parameters as text, CsrfToken as text) as record =>
    let
        // HTTP Basic Authentication details (replace with actual username and password)
        AuthHeader = "Basic " & Binary.ToText(Text.ToBinary(Username & ":" & Password), BinaryEncoding.Base64),

        // Base configuration
        BaseUrl = "https://MYINTERNALRESOURCE",
        RelativeEndpoint = "/odataENDPOINTPATH/Reporting",
        ReportExecutionEndpoint =  RelativeEndpoint & "/Reports('{report_id}')/SOMEBOILERPLATEFUNCTIONExecuteReport",
        Endpoint = Text.Replace(ReportExecutionEndpoint, "{report_id}", ReportId),
        ReportResponse = Web.Contents(
            BaseUrl,
            [
                RelativePath = Endpoint, 
                Headers = [
                    Accept = "application/json",
                    CSRF_NONCE = CsrfToken,
                    Authorization = AuthHeader
                ],
                Content = Text.ToBinary(Parameters),
                ManualStatusHandling = {400, 401, 403, 500} // Handle errors explicitly
            ]
        ),
        ReportJson = Json.Document(ReportResponse)
    in
        ReportJson
in
    ExecuteReport