Express CheckOut Payment Error

[rijsat]

MY expression checkout works in local environment but getting error in production.

Error:

You must provide a request body if you set ContentLength>0 or SendChunked==true.  Do this by calling [Begin]GetRequestStream before [Begin]GetResponse.

Here My Code:

 Public Function HttpCall(ByVal NvpRequest As String) As String
        'CallNvpServer 
        Dim url As String = pendpointurl

        'To Add the credentials from the profile
        Dim codec As New NVPCodec()
        Dim strPost As String = (NvpRequest & "&") + buildCredentialsNVPString()
        strPost = (strPost & "&BUTTONSOURCE=") + HttpUtility.UrlEncode(BNCode)
        'satya
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
        '
        Dim objRequest As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest)
        objRequest.AllowWriteStreamBuffering = False
        objRequest.Timeout = Timeout
        objRequest.Method = "POST"
        objRequest.ContentLength = strPost.Length
        Try
            Using myWriter As New StreamWriter(objRequest.GetRequestStream())
                myWriter.Write(strPost)
            End Using
        Catch e As Exception
            ' 
            ' if (log.IsFatalEnabled) 
            ' { 
            ' log.Fatal(e.Message, this); 
            ' } 

        End Try


        'Retrieve the Response returned from the NVP API call to PayPal 
        Dim objResponse As HttpWebResponse = DirectCast(objRequest.GetResponse(), HttpWebResponse)
        Dim result As String
        Using sr As New StreamReader(objResponse.GetResponseStream())
            result = sr.ReadToEnd()
        End Using

        'Logging the response of the transaction 
        ' if (log.IsInfoEnabled) 
        ' { 
        ' log.Info("Result :" + 
        ' " Elapsed Time : " + (DateTime.Now - startDate).Milliseconds + " ms" + 
        ' result); 
        ' } 
        ' 

        Return result
    End Function