Prova con questo.
codice:
Set Config = Server.CreateObject("CDO.Configuration")
Set Fields = Config.Fields
Fields.Item("http://schemas.microsoft.com/cdo/configuration/SendUsing") = 2
Fields.Item("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "localhost"
Fields.Item("http://schemas.microsoft.com/cdo/configuration/smtpserverPort") = 25
Fields.Update
Dim mail
Set mail = CreateObject("CDO.Message")
Set mail.Configuration = Config
mail.From = "tuaemail@tuodominio.it"
mail.To = "xxx@dominio.it"
mail.Subject = "Tuo oggetto"
mail.HTMLBody = "Tuo testo"
mail.Send
Set mail = Nothing
Set Fields = Nothing
Set Config = Nothing