smtp 邮件发送请求有时失败

Question

我在 C# 中使用以下代码，

string Subject = "test12";     
    MailMessage mail = new MailMessage();
    mail.To.Add(item.ToString());
    mail.From = new MailAddress(EmailUserName);
    mail.Subject = Subject;
    mail.Body = PopulateBody();       
    mail.IsBodyHtml = true;
    SmtpClient client = new SmtpClient(EmailHost, EmailPort);        
    client.EnableSsl = true;
    NetworkCredential credentials = new NetworkCredential(EmailUserName, EmailPassword);

    client.UseDefaultCredentials = false;
    client.Credentials = credentials;
    client.Send(mail);

我在 Client.send(mail) 方法中遇到错误

我尝试过的：

System.Security.Authentication.AuthenticationException: 调用 SSPI 失败，请参阅内部异常。 ---> System.ComponentModel.Win32Exception: 不支持请求的功能 --- 内部异常堆栈跟踪结束 --- 在 System.Net.Security.SslState.StartSendAuthResetSignal（ProtocolToken 消息，AsyncProtocolRequest asyncRequest，Exception 异常）在

Answer 1

我会先尝试不进行身份验证，以检查是否会出现不同的错误，然后再尝试不使用 ssl。

    protected bool NotifyByMail(string server, string strFrom, string strTo, string strSubject, string strBodyText, bool isBodyTextHtml = false)
    {
        if (string.IsNullOrEmpty (server)
            || string.IsNullOrEmpty (strFrom)
            || string.IsNullOrEmpty (strTo)
            || string.IsNullOrEmpty (strSubject)
            || string.IsNullOrEmpty (strBodyText))
            return false;

        try {
            MailAddress from = new MailAddress (strFrom);
            MailAddress to = new MailAddress (strTo);
            MailMessage message = new MailMessage (from, to);

            message.Subject = strSubject;
            message.Body = strBodyText;
            message.IsBodyHtml = isBodyTextHtml;

            SmtpClient client = new SmtpClient (server);

        // Include credentials if the server requires them.
        //client.Credentials = new System.Net.NetworkCredential ("********", "*******");// System.Net.CredentialCache.DefaultNetworkCredentials;

            client.Send (message);
            return true;
        }
        catch (Exception exception) {
                    // TODO ErrorHandling
        }

        return false;
    }

smtp 邮件发送请求有时失败

smtp email send request fails sometimes

c#

email

smtp

sspi