SMTP Authentication in VB 2005

I am trying to authenticate email through SMTP, which I was allways able to do in VB 2003 wihtout too much trouble.

Now in 2005 I cannot get it done. Here is my code (based on the example from this thead:

Code:

---

    Private Sub EmailDistrict1( _
        ByVal StrMailFrom As String, _
        ByVal strMailTo1 As String, _
        ByVal strMailTo2 As String, _
        ByVal strMailTo3 As String, _
        ByVal strMailTo4 As String, _
        ByVal strMailTo5 As String, _
        ByVal strmailto6 As String, _
        ByVal StrSubject As String, _
        ByVal StrBody As String, _
        ByVal strFPath As String)

        Dim message As New MailMessage
        message.From = New MailAddress(StrMailFrom)
        message.To.Add(strMailTo1)
        message.To.Add(strMailTo2)
        message.To.Add(strMailTo3)
        message.To.Add(strMailTo4)
        message.To.Add(strMailTo5)
        message.To.Add(strmailto6)
        message.Subject = StrSubject
        message.Body = StrBody

        Dim emailClient As New SmtpClient(strMailServer)
        emailClient.Credentials = (SMTP_Credentials) ' Formatted as ("User", "Pass")
        emailClient.DeliveryMethod = SmtpDeliveryMethod.Network
        emailClient.UseDefaultCredentials = False
        Try
            emailClient.Send(message)
        Catch ex As Exception
            MessageBox.Show(ex.Message & vbNewLine & ex.stacktrace)
        End Try
    End Sub

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It is VB2005 and I am using Vista as my OS just in case things may be different on that platform. Also the SMTP address is a POP3 email account (provided by the ISP on a domain using Shared Hosting)