主题：腾讯的企业邮箱，怎样用MailSender发邮件，试了很久仍不成功

 你的端口是25才对吧？

 如果要用ssl的话，你要这样发

Dim client As New System.Net.Mail.SmtpClient("smtp.exmail.qq.com", 587) '或者465
client.EnableSsl = True 'SSL

client.Credentials = New System.Net.NetworkCredential("455189993@qq.com", "helen6849338.")
client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network
Dim message As New System.Net.Mail.MailMessage()

message.From = new System.Net.Mail.MailAddress("455189993@qq.com","别名")

'message.To.Add(new System.Net.Mail.MailAddress("2450314695@qq.com","人名"))
message.To.Add("2450314695@qq.com")
message.Subject = "邮件测试"
message.BodyEncoding = System.Text.Encoding.UTF8

Dim content As String

content &= "这是文字" & vbcrlf
content &= "也是文字"

message.Body = content

Try
    client.Send(message)
    msgbox("发送成功")
Catch ex As Exception
    msgbox("发送失败:" & ex.message)
End Try