Troubleshooting .NET Gmail SMTP Email Sending Issues
Many developers encounter problems sending emails via Gmail's SMTP server using .NET. This guide provides solutions and working code examples.
Common Error: "The SMTP server requires a secure connection or the client was not authenticated."
This error indicates that your Gmail SMTP server requires authentication and a secure connection.
Working Code Example:
This C# code snippet demonstrates successful email sending through Gmail's SMTP server:
using System;
using System.Net;
using System.Net.Mail;
namespace EmailSender
{
class Program
{
static void Main(string[] args)
{
// Configure SMTP client
var client = new SmtpClient("smtp.gmail.com", 587)
{
Credentials = new NetworkCredential("[your_email@gmail.com]", "[your_password]"),
EnableSsl = true
};
// Create email message
var message = new MailMessage
{
From = new MailAddress("[your_email@gmail.com]"),
To = { new MailAddress("[recipient_email@example.com]") },
Subject = "Test Email",
Body = "Test email body"
};
// Send email
try
{
client.Send(message);
Console.WriteLine("Email sent successfully!");
}
catch (Exception ex)
{
Console.WriteLine($"Error sending email: {ex.Message}");
}
Console.ReadLine();
}
}
}
Important Note (2021 and Beyond):
For this code to function correctly, you must enable "less secure apps" access in your Gmail security settings. This setting can be found at http://miracleart.cn/link/380714d486fbd50c0c9dfc7e4d8be9f7. This step is crucial to prevent authentication errors like "5.5.1 Authentication Required". Consider using App Passwords for enhanced security instead of your regular password.
Remember to replace placeholders like [your_email@gmail.com], [your_password], and [recipient_email@example.com] with your actual credentials and recipient's email address. If you continue to experience issues, double-check your Gmail settings and ensure that your firewall isn't blocking outgoing SMTP connections.
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