主题：邮箱发送失败

 Dim msg1 As String '’做邮箱发送设置
        Dim m1 As New MailSender
        m1.Host = "smtp.139.com"
        m1.EnableSsl = True '必须将EnableSsl属性设置为True
        m1.Account = "scy"
        m1.Password = "xxx"
        m1.From = "scy@139.com"
        messagebox.Show("1")
        m1.Title = "船舶申报提醒"       
        msg1 = dr("船舶代理") & "已申报船名:" & dr("中文船名") & ",请按要求进行后续工作"      
        m1.Content = msg1
       
        Dim zbkz As String
        Dim zbgy As String
        Dim dr1 As DataRow
        dr1 = DataTables("列表项目").SQLFind("值班日期='" & Date.Today & "'")
       messagebox.Show("2")
       
        If dr1 IsNot Nothing Then '如果找到的话
                 messagebox.Show("3")
           
            If dr1("值班关员") <> "" Then
                    messagebox.Show("4")
                Dim Values() As String
                Values = dr1("值班关员").split("、")
                If values.length > 0 Then
                    For index As Integer = 0 To values.Length - 1
                        Dim dr2 As DataRow = DataTables("登录用户").SQLFind("用户姓名='" & values(index) & "'")
                        If dr2 IsNot Nothing Then
                                 messagebox.Show("5")
                            m1.To = dr2("手机号") & "@139.com"
                            messagebox.Show(dr2("手机号"))
                            m1.SendAsync()
                        End If
                    Next
                End If
               
            End If

设置的中断显示都正常，但是没有收到邮件，也没有发送记录，什么原因呢？