Public Module SendSMTP
    Public Sub SendSMTP(ByVal strFrom As String, ByVal strTo As String, ByVal strSubject As String, ByVal strBody As String, ByVal strCC As String, ByVal strAttachments As String)
        Dim insMail As New MailMessage(New MailAddress(strFrom), New MailAddress(strTo))
        With insMail
            .Subject = strSubject
            .Body = strBody
            .CC.Add(New MailAddress(strCC))
            If Not strAttachments.Equals(String.Empty) Then
                Dim strFile As String
                Dim strAttach() As String = strAttachments.Split(";"c)
                For Each strFile In strAttach
                    .Attachments.Add(New Attachment(strFile.Trim()))
                Next
            End If
        End With
        Dim SmtpUser As New System.Net.NetworkCredential()
        Dim smtp As New System.Net.Mail.SmtpClient
        '-- Define Authenticated User
        SmtpUser.UserName = "something"
        SmtpUser.Password = "somepassword"
        SmtpUser.Domain = "smtp.1und1.de"
        '-- Send Message
        smtp.UseDefaultCredentials = False
        smtp.Credentials = SmtpUser
        smtp.Port = 25
        smtp.Send(insMail)
    End Sub
End Module

'error
SendSMTP("something@something.de", "flo@flo.de", "Subject", "Body here", "CC", "Attachment")