VB.NET Post Request - vb.net

Question

I have looked all over the place for VB.NET support on how to best run this POST request with a JSON, but I keep hitting a 401 Unauthorized error on every method I attempt. When I run this with the same JSON in python I have no issue.
I am using .NET 4.8.03752 and Visual Studio 2019
Public Class MyRequestData
Public Property grant_type As String
Public Property client_id As String
Public Property client_secret As String
Public Property username As String
Public Property password As String
End Class
Public Class MyResponseData
Public Property access_token As String
Public Property refresh_token As String
End Class
Public Class OAuth
Public Shared Async Sub Main()
ServicePointManager.Expect100Continue = True
ServicePointManager.SecurityProtocol = CType(768, SecurityProtocolType) Or CType(3072, SecurityProtocolType)
Dim transaction As New MyRequestData With
{
.grant_type = "password",
.client_id = "MYCLIENTID",
.client_secret = "MYCLIENTSECRET",
.username = "MYUSERNAME",
.password = "MYPASSWORD"
}
Dim content = JsonConvert.SerializeObject(transaction)
Dim buffer = System.Text.Encoding.UTF8.GetBytes(content)
Dim bytes = New Net.Http.ByteArrayContent(buffer)
bytes.Headers.ContentType = New Net.Http.Headers.MediaTypeHeaderValue("application/json")
Dim responseBody As String = Nothing
Using client As New System.Net.Http.HttpClient
Dim response = Await client.PostAsync("MYENDPOINT", bytes)
responseBody = Await response.Content.ReadAsStringAsync()
End Using
Dim data = JsonConvert.DeserializeObject(Of MyResponseData)(responseBody)
Debug.WriteLine(data)
End Sub
End Class