HTTPS — невозможно прочитать данные из транспортного соединения: существующее соединение было принудительно закрыто удаленным узлом.

Я пытаюсь получить доступ к указанному ниже методу API Create. Я получаю следующую ошибку при попытке вызвать webRequest1.GetRequestStream():

Невозможно прочитать данные из транспортного соединения: существующее соединение было принудительно закрыто удаленным узлом.

Код:

Public Function OfferAffirmRequestURL(ByVal strHost As String, ByVal strClientId As String, ByVal strSecretKey As String, ByVal strApiPath As String) As String
    Dim strOfferCommand As String = ""
    Dim strHROBUrl As String = ""
    Dim strHROBRequestURL As String = "https://" & strHost
    Dim strErrorMessage As String

    Dim strXMLString As String = "<?xml version=""1.0"" encoding=""UTF-8""?><Record><ReferenceID>44</ReferenceID><Template>New Offer</Template><RecordData><FormField><candidate_first_name>RBFName16</candidate_first_name><candidate_last_name>LName160</candidate_last_name><candidate_email>[email protected]</candidate_email><candidate_mobile_no>0411111111</candidate_mobile_no><start_date>2014-07-16T00:00:00</start_date></FormField></RecordData></Record>"
    Dim strTimeStamp As String = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ")
    Dim data As String = "clientId" & strClientId & "payload" & strXMLString & "timestamp" & strTimeStamp

    Dim key As Byte() = StringToByteArray(strSecretKey)
    Dim encrypt As HMACSHA1 = New HMACSHA1(key)
    Dim dataBytes As Byte() = Encoding.ASCII.GetBytes(data)
    Dim signatureBytes As Byte() = encrypt.ComputeHash(dataBytes)
    Dim strSignature As String = Convert.ToBase64String(signatureBytes)
    Dim strSignatureParam As String = Uri.EscapeDataString(strSignature)

    strHROBUrl = strHROBRequestURL & strApiPath & "?clientId=" & strClientId & "&payload=" & strXMLString & "&timestamp=" & strTimeStamp & "&signature=" & strSignatureParam

    Dim byteArray As Byte() = Encoding.UTF8.GetBytes(strXMLString)
    ServicePointManager.Expect100Continue = False

    Dim webRequest1 As WebRequest = WebRequest.Create(strHROBUrl)
    'Dim webRequest1 As HttpWebRequest = DirectCast(WebRequest.Create(strHROBUrl), HttpWebRequest)
    webRequest1.Method = "POST"
    webRequest1.ContentType = "text/xml"
    webRequest1.ContentLength = byteArray.Length
    webRequest1.Credentials = CredentialCache.DefaultCredentials

    Try
        Dim requestWriter As IO.Stream = webRequest1.GetRequestStream()
        requestWriter.Write(byteArray, 0, byteArray.Length)
        requestWriter.Close()

        Dim response As WebResponse
        response = webRequest1.GetResponse()
        Dim responseReader As New IO.StreamReader(response.GetResponseStream())

        Dim responseData As String = responseReader.ReadToEnd()
        strErrorMessage = responseData
        responseReader.Close()
        webRequest1.GetResponse().Close()

    Catch ex As WebException
        strErrorMessage = ex.InnerException.Message

    End Try

    Return strErrorMessage
End Function

Вышеупомянутый метод вызывается в методе кнопки Click, показанном ниже:

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim strCreateOfferURL As String = ""
    strCreateOfferURL = OfferAffirmRequestURL("abc.xyz.com", "xyz", "4d8b7jpojpodf031e", "/api/record/createRecord.shtml")
    Label1.Text = strCreateOfferURL
End Sub