I have this code, but keep getting "Failure Sending Email" message

server is smtp.gmail.com
Username is email address

Code works for 1and1 email addresses its just gmail it seems


Code:
 

 Sub SendTheMail()
        rp1.Emailer2(txtto.Text, txtFrom.Text, txtSubject.Text, txtMessage.Text, txtFrom.Text, "smtp.gmail.com", "*******", 465)
  End Sub

  
 Sub Emailer2(ByVal to_who As String, ByVal from_who As String, ByVal txtsubject As String, ByVal txtbody As String, ByVal UserName As String, ByVal smtpServerName As String, ByVal PasswordForEmailServer As String, ByVal aport As Integer)


        Dim SmtpServer As New SmtpClient(smtpServerName, aport)

        SmtpServer.EnableSsl = True

        SmtpServer.Credentials = New Net.NetworkCredential(UserName, PasswordForEmailServer)

        Dim mail As New MailMessage(from_who, to_who, txtsubject, txtbody)

        Try
            SmtpServer.Send(mail)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try




    End Sub
Help is appreciated