Office 365 SMTP vb.net

Question

I developed a vp.net web app contains a function that sends emails it was running normally until last Monday any suggestions. the following code explain what I am using to use smtp.office365.com:-

 `Dim SendMessage As New MailMessage

    SendMessage.To.Add("ToMail")
    SendMessage.CC.Add("CCMail")
    SendMessage.From = New MailAddress("MyMail")
    SendMessage.Subject = subject

    SendMessage.Body = "Test"

    SendMessage.IsBodyHtml = True

    Try


        Dim client As New SmtpClient("smtp.office365.com", 587)
        SendMessage.Priority = MailPriority.High
        client.EnableSsl = True

        client.UseDefaultCredentials = False
        Dim x As New Net.NetworkCredential("Mail", "Password")
        client.Credentials = x

        client.DeliveryMethod = SmtpDeliveryMethod.Network
        client.SendAsync(SendMessage, Nothing)


    Catch ex As Exception
        MsgBox(ex.ToString())


    End Try`

Answer 1

问题出在防火墙阻止了端口587和25