c# - 服务器响应是： 5.7.0 必须首先发出 STARTTLS 命令。i16sm1806350pag.18 - gsmtp

Question

我正在尝试使用 gmail 发送邮件，但我遇到了一个异常The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Must issue a STARTTLS command first. i16sm1806350pag.18 - gsmtp

我为发送邮件编写的代码是：

MailMessage mail = new MailMessage(); 
mail.To.Add(txtEmail.Text.Trim()); 
mail.To.Add("Secondry@gmail.com");
mail.From = new MailAddress("mysendingmail@gmail.com");
mail.Subject = "Confirmation of Registration on Job Junction.";
string Body = "Hi, this mail is to test sending mail using Gmail in ASP.NET";
mail.Body = Body;
mail.IsBodyHtml = true;
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
// smtp.Host = "smtp.gmail.com"; //Or Your SMTP Server Address
smtp.Credentials = new System.Net.NetworkCredential("mysendingmail@gmail.com", "password");
// smtp.Port = 587;
//Or your Smtp Email ID and Password
smtp.UseDefaultCredentials = false;
// smtp.EnableSsl = true;
smtp.Send(mail);

请告诉我解决方案，我没有得到任何解决此异常的方法。

score 60 · Accepted Answer

Step (1): smtp.EnableSsl = true;

if not enough:

Step (2): "Access for less secure apps" must be enabled for the Gmail account used by the NetworkCredential using google's settings page:

score 42 · Accepted Answer

Gmail requires you to use a secure connection. This can be set in your web.config like this:

<network host="smtp.gmail.com" enableSsl="true" ... />

OR

The SSL should be enable on the webserver as well. Refer following link

Enabling SSL on IIS 7.0

score 12 · Accepted Answer

这个问题也困扰了我一夜。以下是解决方法：

将主机设置为：smtp.gmail.com
将端口设置为：587

这是 TLS 端口。我一直在使用所有其他 SMTP 端口，但没有成功。如果你enableSsl = true这样设置：

Dim SMTP As New SmtpClient(HOST)
SMTP.EnableSsl = True

修剪用户名和密码字段（如果用户像我一样在注册时输入电子邮件和密码，这是防止错误的好方法），如下所示：

SMTP.Credentials = New System.Net.NetworkCredential(EmailFrom.Trim(), EmailFromPassword.Trim())

使用 TLS 端口会将您的 SMTP 视为允许您进行身份验证的 SMTPS。我立即收到来自 Google 的警告，说我的电子邮件阻止了具有安全风险或已过时的应用程序。我继续“打开不太安全的应用程序”。然后我更新了关于我的电话号码的信息，谷歌通过短信向我发送了一个验证码。我进去了，瞧！

我再次运行应用程序，它成功了。我知道这个线程很旧，但我在网上搜索了它抛出的所有异常并在每行之后添加 MsgBoxes 以查看出了什么问题。这是我为便于阅读而修改的工作代码，因为我的所有变量都来自 MySQL 数据库：

Try
    Dim MySubject As String = "Email Subject Line"
    Dim MyMessageBody As String = "This is the email body."
    Dim RecipientEmail As String = "recipient@gmail.com"
    Dim SenderEmail As String = "sender@gmail.com"
    Dim SenderDisplayName As String = "FirstName LastName"
    Dim SenderEmailPassword As String = "SenderPassword4Gmail"

    Dim HOST = "smtp.gmail.com"
    Dim PORT = "587" 'TLS Port
    
    Dim mail As New MailMessage
    mail.Subject = MySubject
    mail.Body = MyMessageBody
    mail.To.Add(RecipientEmail) 
    mail.From = New MailAddress(SenderEmail, SenderDisplayName)

    Dim SMTP As New SmtpClient(HOST)
    SMTP.EnableSsl = True
    SMTP.Credentials = New System.Net.NetworkCredential(SenderEmail.Trim(), SenderEmailPassword.Trim())
    SMTP.DeliveryMethod = SmtpDeliveryMethod.Network 
    SMTP.Port = PORT
    SMTP.Send(mail)
    MsgBox("Sent Message To : " & RecipientEmail, MsgBoxStyle.Information, "Sent!")
Catch ex As Exception
    MsgBox(ex.ToString)
End Try

我希望这段代码可以帮助 OP，但也希望像我这样迟到的人。享受。

score 8 · Accepted Answer

“ https://www.google.com/settings/security/lesssecureapps ” 登录您的gmail帐户后使用此链接并单击打开。然后运行您的应用程序，它肯定会工作。

score 5 · Accepted Answer

发送按钮逻辑：

string fromaddr = "YOURMAILID@gmail.com";
string toaddr = TextBox1.Text;//TO ADDRESS HERE
string password = "YOUR PASSWROD";

MailMessage msg = new MailMessage();
msg.Subject = "Username &password";
msg.From = new MailAddress(fromaddr);
msg.Body = "Message BODY";
msg.To.Add(new MailAddress(TextBox1.Text));
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.Port = 587;
smtp.UseDefaultCredentials = false;
smtp.EnableSsl = true;
NetworkCredential nc = new NetworkCredential(fromaddr,password);
smtp.Credentials = nc;
smtp.Send(msg);

此代码 100% 有效。如果您的系统或防火墙中有防病毒软件限制从您的系统发送邮件，请禁用您的防病毒软件和防火墙。在此运行此代码之后...在上面的代码中，TextBox1.Text控件用于TOaddress.

score 3 · Accepted Answer

对于像我这样的非常基本的用户，来自 (FromEmailAddress) 的电子邮件是在 Gmail 上创建的实际电子邮件地址，您还需要设置不太安全的应用程序访问才能使其正常工作。 https://myaccount.google.com/lesssecureapps

那么语句的顺序也应该是正确的。

    public static bool SendEmail(string body, string subject, string toEmail)
            {
                MailAddress fromAddress = new MailAddress("noreply.mymail@gmail.com", "Mail Support");
                MailAddress toAddress = new MailAddress(toEmail, "Dear Customer");
                const string fromPassword = "mymail_login_password.";
                SmtpClient smtpClient = new SmtpClient();
                smtpClient.UseDefaultCredentials = false;
                smtpClient.Credentials = new NetworkCredential(fromAddress.Address, fromPassword);
                smtpClient.Host = "smtp.gmail.com";
                smtpClient.Port = 587;
                smtpClient.EnableSsl = true;
                smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
                MailMessage mailMessage = new 
MailMessage(fromAddress.Address,toAddress.Address,subject, body);
                try
                {
                    smtpClient.Send(mailMessage);
                    return true;
                }
                catch (SmtpException ex)
                {
                      return false;
                }
            }

score 3 · Accepted Answer

如果您（像我一样）通过系统传递所有参数，如port，username，password并且您不允许修改代码，那么您可以在以下位置进行简单的更改web.config：

<system.net>
  <mailSettings>
    <smtp>
      <network enableSsl="true"/>
    </smtp>
  </mailSettings>
</system.net>

score 3 · Accepted Answer

如果在按照建议将该参数添加到 web.config 时收到错误“无法识别的属性 'enableSsl'”。我发现我可以通过将其添加到我的代码文件中来解决该错误，而不是以这种格式：

SmtpClient smtp = new SmtpClient();
smtp.EnableSsl = true;

try
{
    smtp.Send(mm);
}
catch (Exception ex)
{
    MsgBox("Message not emailed: " + ex.ToString());
}

这是我的 web.config 的 system.net 部分：

<system.net>
  <mailSettings>
    <smtp from="<from_email>">
      <network host="smtp.gmail.com"
       port="587"
       userName="<your_email>"
       password="<your_app_password>" />
    </smtp>
  </mailSettings>
</system.net>

score 3 · Accepted Answer

使用代码我也遇到了同样的错误：

MailMessage mail = new MailMessage(); 
mail.To.Add(txtEmail.Text.Trim()); 
mail.To.Add("Secondry@gmail.com");
mail.From = new MailAddress("mysendingmail@gmail.com");
mail.Subject = "Confirmation of Registration on Job Junction.";
string Body = "Hi, this mail is to test sending mail using Gmail in ASP.NET";
mail.Body = Body;
mail.IsBodyHtml = true;
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
// smtp.Host = "smtp.gmail.com"; //Or Your SMTP Server Address
smtp.Credentials = new System.Net.NetworkCredential("mysendingmail@gmail.com", "password");
// smtp.Port = 587;
//Or your Smtp Email ID and Password
smtp.UseDefaultCredentials = false;
// smtp.EnableSsl = true;
smtp.Send(mail);

但是向上移动 2 行解决了这个问题：

MailMessage mail = new MailMessage(); 
mail.To.Add(txtEmail.Text.Trim()); 
mail.To.Add("Secondry@gmail.com");
mail.From = new MailAddress("mysendingmail@gmail.com");
mail.Subject = "Confirmation of Registration on Job Junction.";
string Body = "Hi, this mail is to test sending mail using Gmail in ASP.NET";
mail.Body = Body;
mail.IsBodyHtml = true;
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
// smtp.Host = "smtp.gmail.com"; //Or Your SMTP Server Address
smtp.UseDefaultCredentials = false;
smtp.EnableSsl = true;
smtp.Credentials = new System.Net.NetworkCredential("mysendingmail@gmail.com", "password");
// smtp.Port = 587;
//Or your Smtp Email ID and Password
smtp.Send(mail);

score 1 · Accepted Answer

登录您的 gmail 帐户https://myaccount.google.com/u/4/security-checkup/4

（见图）查看 Google 可能因“未知”或可疑活动而阻止的所有位置。

score 0 · Accepted Answer

**this is first  part of program**
<head runat="server">
    <title></title>
    <style>
        .style4
        {
            margin-left:90px;
        }
        .style3{
            margin-left:130px;
        }
        .style2{
            color:white;
            margin-left:100px;
            height:400px;
            width:450px;
            text-align:left;
                }
        .style1{
            height:450px;
            width:550px;
            margin-left:450px;
            margin-top:100px;
            margin-right:500px;
            background-color:rgba(0,0,0,0.9);
        }
        body{
            margin:0;
            padding:0;
        }
        body{
            background-image:url("/stock/50.jpg");
            background-size:cover;
            background-repeat:no-repeat;
            }   
       </style>
</head>
<body>
    <form id="form1" runat="server">
        <div>

            <div class="style1">
                <table class="style2">
                   <tr>
                       <td colspan="2"><h1 class="style4">Sending Email</h1></td>
                   </tr>
                   <tr>
                       <td>To</td>
                       <td><asp:TextBox ID="txtto" runat="server" Height="20px" Width="250px" placeholder="Abc@gmail.com"></asp:TextBox><asp:RequiredFieldValidator ForeColor="Red" runat="server" ErrorMessage="Required" ControlToValidate="txtto" Display="Dynamic"></asp:RequiredFieldValidator><asp:RegularExpressionValidator runat="server" ForeColor="Red" ControlToValidate="txtto" Display="Dynamic" ErrorMessage="Invalid Email_ID" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator> </td>
                   </tr>
                     <tr>
                       <td>From</td>
                       <td><asp:TextBox ID="txtfrom" runat="server" Height="20px" Width="250px" placeholder="xyz@gmail.com"></asp:TextBox> <asp:RequiredFieldValidator ForeColor="Red" Display="Dynamic" runat="server" ErrorMessage="Required" ControlToValidate="txtfrom"></asp:RequiredFieldValidator>
                           <asp:RegularExpressionValidator Display="Dynamic" runat="server" ErrorMessage="Invalid Email-ID" ControlToValidate="txtfrom" ForeColor="Red" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator>
                         </td>
                   </tr>
                     <tr>
                       <td>Subject</td>
                       <td><asp:TextBox ID="txtsubject" runat="server" Height="20px" Width="250px" placeholder="Demonstration on Youtube"></asp:TextBox><asp:RequiredFieldValidator ForeColor="Red" runat="server" ErrorMessage="Required" ControlToValidate="txtsubject"></asp:RequiredFieldValidator> </td>
                   </tr>
                     <tr>
                       <td>Body</td>
                       <td><asp:TextBox ID="txtbody" runat="server" Width="250px" TextMode="MultiLine" Rows="5" placeholder="This is the body text"></asp:TextBox><asp:RequiredFieldValidator ForeColor="Red" runat="server" ErrorMessage="Required" ControlToValidate="txtbody"></asp:RequiredFieldValidator> </td>
                   </tr>
                     <tr>
                       <td colspan="2"><asp:Button CssClass="style3" BackColor="Green" BorderColor="green" ID="send" Text="Send" runat="server" Height="30px"  Width="100px" OnClick="send_Click"/></td>
                     </tr>
                    <tr>
                        <td colspan="2"><asp:Label ID="lblmessage" runat="server"></asp:Label> </td>
                    </tr>
               </table>
            </div>

        </div>
    </form>
</body>
</html>


**this is second part of program**

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net.Mail;

namespace WebApplication6
{
    public partial class sendingemail1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void send_Click(object sender, EventArgs e)
        {
            try
            {
                MailMessage message = new MailMessage();
                message.To.Add(txtto.Text);
                message.Subject = txtsubject.Text;
                message.Body = txtbody.Text;
                message.From = new MailAddress(txtfrom.Text);
                SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
                client.EnableSsl = true;
                client.Credentials = new System.Net.NetworkCredential(txtfrom.Text, "Sunil@123");
                for(int i=1;i<=100;i++)
                { 
                client.Send(message);
                lblmessage.Text = "Mail Successfully send";
                }
            }
            catch (Exception ex)
            {
                lblmessage.Text = ex.Message;
            }
        }
    }
}

score 0 · Accepted Answer

0

Note to self: "Remove UseDefaultCredentials = false".

于 2020-07-07T07:13:01.763 回答

score 0 · Accepted Answer

我创建没有任何电话号码或相关电子邮件的新电子邮件，然后打开与我一起完成的不太安全的应用程序访问

c# - 服务器响应是： 5.7.0 必须首先发出 STARTTLS 命令。i16sm1806350pag.18 - gsmtp

13 回答 13

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