L'envoi des emails en vb.net

Bonjour,
j'ai programmé un programme qui permt d'envoyer des emails en vb.net mais malheuresement ne fonctionne pas .....................?????
Sub mainevents()
Try
MyMailMessage.From = New MailAddress(TextBox1.Text)
MyMailMessage.To.Add(TextBox2.Text)
MyMailMessage.Subject = TextBox3.Text
MyMailMessage.Body = TextBox4.Text
Dim SMPT As New SmtpClient(TextBox6.Text)
SMPT.Port = TextBox5.Text
If CheckBox1.Checked = True Then
SMPT.EnableSsl = True
ElseIf CheckBox1.Checked = False Then
SMPT.EnableSsl = False
End If
SMPT.Credentials = New System.Net.NetworkCredential(TextBox7.Text, TextBox8.Text)
SMPT.Send(MyMailMessage)
Catch ex As Exception
End Try
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Call MainEvents()
MsgBox("Message envoyé avec succès", MsgBoxStyle.Information, "Info")
End Sub