[RESOLVED] Threading and Sending Mail

[dr_aybyd]

I am getting error when I am putting my sendmail function into other thread.
But without threading the message was sent successfully.
I am getting error in this part when sending using thread.

mail.Body = EmailBody.DocumentText
It say: Specified cast is not valid.

Here is my code for sending email
EmailBody is a webbrowser in Desing MOde ON

Private Sub SendMail()
        Try
            Dim SmtpServer As New SmtpClient()
            Dim mail As New MailMessage()
            SmtpServer.Credentials = New  _
            Net.NetworkCredential("username", "password")
            SmtpServer.Port = 587
            SmtpServer.EnableSsl = True
            SmtpServer.Host = "pod51003.outlook.com"
            mail = New MailMessage()
            mail.From = New MailAddress("email")
            mail.To.Add("toemail")
            mail.CC.Add("CCemail")
            mail.Subject = "Test Mail"
            mail.IsBodyHtml = True
            mail.Body = EmailBody.DocumentText
            SmtpServer.Send(mail)
            TSSLstatus.Text = "Email successfully sent...."
            Me.Cursor = Cursors.Arrow
            MsgBox("mail send")
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
    End Sub

And this is how I start the thread and call the sendmail

Private Sub btnSend_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSend.Click
        TSSLstatus.Text = "Please wait, sending email..."
        Dim t As Thread
        t = New Thread(AddressOf Me.SendMail)
        t.Start()
End Sub

What I am missing for?
I need to put in other thread so that my Form is active while sending big email.