C# 我在代码中遇到了一个异常，比如未经验证 SmtpClient-SmtpClient=newsmtpclient（“smtp.gmail.com”）； smtpClient.EnableSsl=true； smtpClient.Port=587； smtpClient.Credentials=新系统.Net.NetworkCredential（“xxxxxx@gmail.com","xxxxxxxx","smtp.gmail.com",； smtpClient.UseDefaultCredentials=false； MailMessage MailMessage=新建MailMessage（）； mailMessage.To.Add（TextBox2.Text.Trim（））； mailMessage.From=新邮件地址（“xxxxxx@gmail.com"); mailMessage.IsBodyHtml=true； mailMessage.Subject=“感谢注册医生搜索”； mailMessage.Body=“”； smtpClient.Send（mailMessage）；

我得到一个错误：

SMTP服务器需要安全连接，或者客户端未通过身份验证。服务器响应为：需要5.5.1身份验证

我不明白它背后的原因是什么

我使用这个：

SmtpClient smtpClient = new SmtpClient("smtp.gmail.com");
smtpClient.EnableSsl = true;
smtpClient.Port = 587;
smtpClient.Credentials = new System.Net.NetworkCredential("xxxxxx@gmail.com", "xxxxxxxx", "smtp.gmail.com");
smtpClient.UseDefaultCredentials = false;

MailMessage mailMessage = new MailMessage();
mailMessage.To.Add(TextBox2.Text.Trim());
mailMessage.From = new MailAddress("xxxxxx@gmail.com");
mailMessage.IsBodyHtml = true;
mailMessage.Subject = "Thanks for registering to Doctor Search";
mailMessage.Body = "<a href='http://localhost:1668/templatemo_418_form_pack/OTP.aspx?ctk=" + ss + "'>Click here to verify your Mobile</a>";

smtpClient.Send(mailMessage);

---

您是否能够使用传递到smtp凭据的凭据从浏览器登录到Gamil？我收到一个异常，因为smtp服务器需要安全连接，或者客户端未经过身份验证。服务器响应为：需要5.5.1身份验证。

public void SendEmailWithGmail(string emailContent, string emailRecipients, string emailSubject)
    {
        var @from = _emailSendFrom;  //Replace this with your own correct Gmail Address

        var _to = emailRecipients;


        var mail = new System.Net.Mail.MailMessage();
        mail.To.Add(_to);
        mail.From = new System.Net.Mail.MailAddress(@from, _emailDisplayName, System.Text.Encoding.UTF8);           

        mail.Subject = emailSubject;
        mail.SubjectEncoding = System.Text.Encoding.UTF8;
        mail.Body = emailContent;
        mail.BodyEncoding = System.Text.Encoding.UTF8;
        mail.IsBodyHtml = true;
        mail.Priority = System.Net.Mail.MailPriority.High;


        var client = new SmtpClient
        {
            Credentials = new System.Net.NetworkCredential(@from, GmailPsw),
            Port = 587,
            Host = "smtp.gmail.com",
            EnableSsl = true
        };


            client.Send(mail);

    }