Windows 7 program no longer working on windows 10 for wordpress/woocommerce API

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VB

We have a VB 2010 Desktop program (built and deployed to msi) .Net 4.5 program that has been working for years on all supported versions of Windows.

Over the past few weeks it no longer works correctly on Windows 10 including our client and from our development system.

It is actually trying to get orders from the WordPress/WooCommerce API (WP API V1 or V2).

The error received is
One or more errors occurred. An error occurred while sending the request.

Using client As HttpClient = New HttpClient()
                client.DefaultRequestHeaders.Accept.Add(New MediaTypeWithQualityHeaderValue("application/json"))
                Dim v As Object = Nothing
                If pJSON = NIL Then

                    v = client.GetStringAsync(pURL)
                Else
                    Static myTestSwt As Boolean = False
                    If MyTesting AndAlso TestingDontUpdate Then
                        If Not myTestSwt Then
                            Stop
                            myTestSwt = True
                        End If
                    End If

                    Dim requestMessage = New HttpRequestMessage
                    Dim httpContent As StringContent = New StringContent(pJSON, Encoding.UTF8, "application/json")

                    Dim result As HttpResponseMessage = Nothing ' As Object = Nothing

                    result = client.PutAsync(pURL, httpContent).Result
                    If result.IsSuccessStatusCode Then
                        funRC = True
                        pOutJSON = "{""AaaTeXStatus"": ""OK""}"
                    Else
                        pOutReason = result.StatusCode & Sp & result.ReasonPhrase ' & SP & requestMessage.ToString
                    End If

                    GoTo ExitFunction
                End If

                If v Is Nothing Then
                    GoTo ExitFunction
                End If
                If v.Result Is Nothing Then  ' 401 unauthorized ' should be json
                    GoTo ExitFunction
                End If
                pOutJSON = v.Result  '  json response
            End Using
Catch ex As Exception
            pOutReason = ex.Message
            If ex.InnerException IsNot Nothing Then pOutReason &= Sp & ex.InnerException.Message
 
        End Try

What I have tried:

On Windows 7 works from VS 2010 IDE and exe.
On Windows 10 worked from VS 2017 IDE.