系统 CentOs 7

发送邮件,本地测试OK , 发布后报错

System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.

使用自带的Smtp和MailKit.Smtp 均无效

提示应该是证书问题.

代码如下 :

 1 MailMessage mailMsg = new MailMessage();//实例化对象
 2             mailMsg.From = new MailAddress("xxxx", "xxxx");//源邮件地址和发件人
 3             mailMsg.To.Add(new MailAddress("xxx@126.com"));//收件人地址
 4             mailMsg.Subject = "邮件发送测试";//发送邮件的标题
 5             StringBuilder sb = new StringBuilder();
 6             sb.Append("测试测试测试测试");
 7             sb.Append("嘿嘿");
 8             mailMsg.Body = sb.ToString();//发送邮件的内容
 9             //指定smtp服务地址（根据发件人邮箱指定对应SMTP服务器地址）
10             System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient();//格式：smtp.126.com  smtp.164.com
11             client.Host = "smtp.xxx.com";
12             //要用587端口
13             client.Port = 587;//端口
14             //加密
15             client.EnableSsl = true;
16             //通过用户名和密码验证发件人身份
17             client.Credentials = new NetworkCredential("xxx@xxx.com", "xxxxxxx"); // 
18             //发送邮件
19             try
20             {
21                 client.Send(mailMsg);
22                 return "success";
23             }
24             catch (Exception ex)
25             {
26                 return ex.ToString();
返回具体信息
System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
   at System.Net.Security.SslStream.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, ExceptionDispatchInfo exception)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessAuthentication(LazyAsyncResult lazyResult, CancellationToken cancellationToken)
   at System.Net.Security.SslStream.AuthenticateAsClient(SslClientAuthenticationOptions sslClientAuthenticationOptions)
   at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
   at System.Net.TlsStream.AuthenticateAsClient()
   at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpClient.GetConnection()
   at System.Net.Mail.SmtpClient.Send(MailMessage message)


这会是什么问题呢? 求赐教
                        .NetCore