probabilmente devi autenticarti sul server
codice:
Dim msg as new System.Web.Mail.MailMessage()
msg.Subject = "Test"
msg.Body = "Questo è il testo della mail"
msg.To = "victor8872@libero.it"
msg.From = "dansalsa@dansalsa.it"
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/smtpserver", "smtp.paclemanzoni.it" )
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/smtpserverport", 25 )
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendusing", 2 )
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1 )
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendusername", "username" )
msg.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendpassword", "password" )
SmtpMail.Send( msg )