C# Gmail SMTP: How to send emails after recent changes?

Other Questions Gmail
1

Hey everyone, I’m stuck trying to send emails through Gmail using SMTP in C#. I’ve got this code that used to work, but now it’s throwing an error about authentication. Here’s what I’m dealing with:

SmtpClient emailClient = new SmtpClient
{
    Port = 587,
    Host = "smtp.gmail.com",
    EnableSsl = true,
    Credentials = new NetworkCredential("[email protected]", "mypassword")
};

MailMessage msg = new MailMessage
{
    From = new MailAddress("[email protected]"),
    Subject = "Test Email",
    Body = "This is a test message"
};
msg.To.Add("[email protected]");

emailClient.Send(msg);

When I run this, I get an error saying the SMTP server needs a secure connection or authentication failed. I know Gmail got rid of the ‘Less secure app access’ option, and now they’ve even removed the ‘App passwords’ section from 2-Step Verification.

So what’s the deal? How are we supposed to send emails through Gmail with C# now? Any help would be awesome because I’m totally lost here. Thanks!

2

hey there! i ran into the same issue recently. Google’s made it trickier, but there’s a workaround. You gotta use OAuth 2.0 now instead of password auth. It’s a bit more complex, but basically you need to set up a project in Google Cloud Console, enable Gmail API, and get client credentials. Then use those in your C# code with a library like Google.Apis.Gmail.v1. It’s a pain, but it works!

3

I’ve wrestled with this problem too. One approach that’s worked for me is using Microsoft’s Graph API for sending emails through Office 365. It’s a bit of a shift from Gmail, but it’s robust and well-documented.

You’ll need to set up an Azure AD application and get the necessary credentials. Then, you can use the Microsoft.Graph NuGet package in your C# code. It’s more involved initially, but once set up, it’s quite straightforward to use.

Here’s a basic snippet to give you an idea:

var graphClient = new GraphServiceClient(authProvider);
var message = new Message
{
    Subject = "Test Email",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "This is a test message"
    },
    ToRecipients = new List<Recipient>()
    {
        new Recipient
        {
            EmailAddress = new EmailAddress
            {
                Address = "[email protected]"
            }
        }
    }
};

await graphClient.Me.SendMail(message, true).Request().PostAsync();

It’s been reliable for me, and you don’t have to worry about changing Gmail policies.

4

I’ve encountered this issue as well. Google’s security changes have indeed made the process more complex. While OAuth 2.0 is one solution, another option is to use a third-party SMTP service like SendGrid or Mailgun. These services often provide simpler integration and can be more reliable for sending emails at scale. They usually offer free tiers for low volume sending, which might suffice for your needs. Additionally, they typically provide better deliverability rates and analytics. If you’re not comfortable with implementing OAuth 2.0, this could be a viable alternative worth exploring.