部署到主机后，使用 Gmail 通过 C# 发送邮件不起作用

Question

我正在尝试通过 Gmail 发送邮件。当我在 localhost 上测试时，我发送邮件成功，但是当我将它上传到 web 主机时，这不起作用。我看到了这种类型的错误：

Request for the permission of type System.Net.Mail.SmtpPermission, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 failed.

每当我使用端口 25 时，都会收到以下此类错误：

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required

下面是我发送邮件的代码。

MailMessage mail = new MailMessage("host@gmail.com","User@gamil.com");

SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");              
mail.Subject = "Any String" 
mail.Body = mailbody;
mail.IsBodyHtml = true;
SmtpServer.Port = 587;
SmtpServer.DeliveryMethod = SmtpDeliveryMethod.Network;
SmtpServer.UseDefaultCredentials = false;
SmtpServer.Credentials = new System.Net.NetworkCredential("xyz@gmail.com","123");               
SmtpServer.EnableSsl = true;

SmtpServer.Send(mail);

有什么解决办法吗？请给我建议！

Answer 1

编辑： OP 添加了对回答这个问题至关重要的额外信息，但我保留了旧答案，因为它可能仍然对某人有帮助

新答案： This Whosebug 问题已经回答了这个问题

旧答案： 由于 this Whosebug 答案已经回答，您将 SMTP 服务器上的端口更改为 587 而不是默认值 (25)，这需要提升权限导致此错误更改为：

SmtpServer.Port = 587;

对此：

SmtpServer.Port = 25;

它应该可以工作

注意： 使用 SSL 时，端口需要 443

Answer 2

答案：你的代码加上SmtpDeliveryFormat.SevenBit

示例：

using (SmtpClient smtp = new SmtpClient())
                {
                    NetworkCredential credential = new NetworkCredential
                    {
                        UserName = WebConfigurationManager.AppSettings["UserName"],
                        Password = WebConfigurationManager.AppSettings["Password"],
                    };
                    smtp.Credentials = credential;
                    smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                    smtp.DeliveryFormat = SmtpDeliveryFormat.SevenBit;
                    smtp.Host = WebConfigurationManager.AppSettings["Host"];
                    smtp.Port = WebConfigurationManager.AppSettings["Port"].ToNcInt();
                    smtp.EnableSsl = Convert.ToBoolean(WebConfigurationManager.AppSettings["EnableSsl"]);
                    smtp.Send(mail);
                }

Answer 3

试试这个

using System;
using System.Net;
using System.Net.Mail;

namespace AmazonSESSample
{
    class Program
{
    static void Main(string[] args)
    {
        // Replace sender@example.com with your "From" address. 
        // This address must be verified with Amazon SES.
        String FROM = "a@a.com";
        String FROMNAME = "ABC";

        // Replace recipient@example.com with a "To" address. If your account 
        // is still in the sandbox, this address must be verified.
        String TO = "a@a.com";

        // Replace smtp_username with your Amazon SES SMTP user name.
        String SMTP_USERNAME = "a@a.com";

        // Replace smtp_password with your Amazon SES SMTP user name.
        String SMTP_PASSWORD = "ASJKAJSN";

        // (Optional) the name of a configuration set to use for this message.
        // If you comment out this line, you also need to remove or comment out
        // the "X-SES-CONFIGURATION-SET" header below.
        String CONFIGSET = "ConfigSet";

        // If you're using Amazon SES in a region other than US West (Oregon), 
        // replace email-smtp.us-west-2.amazonaws.com with the Amazon SES SMTP  
        // endpoint in the appropriate AWS Region.
        String HOST = "smtp-relay.sendinblue.com";

        // The port you will connect to on the Amazon SES SMTP endpoint. We
        // are choosing port 587 because we will use STARTTLS to encrypt
        // the connection.
        int PORT = 587;

        // The subject line of the email
        String SUBJECT =
            "Amazon SES test (SMTP interface accessed using C#)";

        // The body of the email
        String BODY =
            "<h1>Amazon SES Test</h1>" +
            "<p>This email was sent through the " +
            "<a href='https://aws.amazon.com/ses'>Amazon SES</a> SMTP interface " +
            "using the .NET System.Net.Mail library.</p>";

        // Create and build a new MailMessage object
        MailMessage message = new MailMessage();
        message.IsBodyHtml = true;
        message.From = new MailAddress(FROM, FROMNAME);
        message.To.Add(new MailAddress(TO));
        message.Subject = SUBJECT;
        message.Body = BODY;
        // Comment or delete the next line if you are not using a configuration set
        message.Headers.Add("X-SES-CONFIGURATION-SET", CONFIGSET);

        using (var client = new System.Net.Mail.SmtpClient(HOST, PORT))
        {
            // Pass SMTP credentials
            client.Credentials =
                new NetworkCredential(SMTP_USERNAME, SMTP_PASSWORD);

            // Enable SSL encryption
            client.EnableSsl = true;

            // Try to send the message. Show status in console.
            try
            {
                Console.WriteLine("Attempting to send email...");
                client.Send(message);
                Console.WriteLine("Email sent!");
            }
            catch (Exception ex)
            {
                Console.WriteLine("The email was not sent.");
                Console.WriteLine("Error message: " + ex.Message);
            }
        }
    }
}

}

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