警告：请勿在生产代码中使用此功能！

解决方法是，您可以关闭证书验证。只有这样做才能获得由于证书错误而引发错误的确认。

在调用之前调用此方法

smtpclient.Send()

    [Obsolete("Do not use this in Production pre!!!",true)]    static void NEVER_EAT_POISON_Disable_Certificatevalidation()    {        // Disabling certificate validation can expose you to a man-in-the-middle attack        // which may allow your encrypted message to be read by an attacker        // https://stackoverflow.com/a/14907718/740639        ServicePointManager.ServerCertificatevalidationCallback = delegate (     object s,     X509Certificate certificate,     X509Chain chain,     SslPolicyErrors sslPolicyErrors ) {     return true; };    }