使用SMTP通过C#从Office 365邮箱发送电子邮件

Question

我有一个控制台应用程序，我需要通过它发送电子邮件通知。我可以在浏览器中使用相同的凭据登录邮箱。

从抛出的异常来看，我似乎无法通过C#代码打开与Office OWA的连接，并收到错误消息：“发送邮件失败”-内部异常-“无法连接到远程服务器”。

我注意到，从浏览器登录邮箱时，它首先让我根据电子邮件地址域登录公司特定页面，然后要求输入密码登录邮箱。

此外，传递给打开 smtpClient connect 的网络凭据需要在 Office 365 中具有一些管理员权限或提升的权限，或者它可以是具有邮箱的常规 Office 365 用户。

参考博客：

https://weblogs . ASP . net/sreejukg/send-email-using-office-365-account-and-c？__r=8d721ba733714a1

https://learn.microsoft.com/en-us/Exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-office-3?redirectSourcePath=%2farticle%2fHow-to-set-up-a-multifunction-device-or-application-to-send-email-using-Office-365-69f58e99-c550-4274-ad18-c805d654b4c4#HowtoconfigSMTPCS

try
            {
                String userName = "[e-mail]";
                String password = "passwordgoeshere";
                MailMessage msg = new MailMessage();
                msg.To.Add(new MailAddress("[e-mail]"));
                msg.From = new MailAddress(userName);
                msg.Subject = "Test Office 365 Account";
                msg.Body = "Testing email using Office 365 account.";
                msg.IsBodyHtml = true;

                using (SmtpClient client = new SmtpClient
                {
                    Host = "smtp.office365.com",
                    Credentials = new System.Net.NetworkCredential(userName, password),
                    Port = 587,
                    EnableSsl = true,
                })
                {
                    client.Send(msg);
                }
            }
            catch (Exception ex)
            {
                Console.Write(ex.Message);
                Console.ReadKey();
            }

1. 如果我使用共享邮箱凭据打开连接，我应该能够从共享邮箱发送电子邮件。

Answer 1

请添加UseDefaultCredentials = false，否则它将选择系统或经过身份验证的用户凭据来发送电子邮件

            using (SmtpClient client = new SmtpClient
            {
                Host = "smtp.office365.com",
                Credentials = new System.Net.NetworkCredential(userName, password),
                Port = 587,
                EnableSsl = true,
                UseDefaultCredentials = false
            })
            {
                client.Send(msg);
            }

还是推荐这样设定

        using (SmtpClient client = new SmtpClient
        {
            Host = "smtp.office365.com",
            Credentials = new System.Net.NetworkCredential(userName, password),
            Port = 587,
            EnableSsl = true
        })
        {
            client.UseDefaultCredentials = false;
            client.Send(msg);
        }