MailKit: throws Authentication Failed while calling Authenticate method from the Pop3Client class

Question

I am using MailKit for sending and receiving emails. but when I try to get emails, I get the Authentication Failed error. here is my code:

using MailKit.Net.Pop3;
using MimeKit;

public List<Email> GetEmails()
{
    using var emailClient = new Pop3Client();
    emailClient.Connect("pop.mail.yahoo.com", 995, true);
    emailClient.AuthenticationMechanisms.Remove("XOAUTH2"); //commenting this line won't help.
    emailClient.Authenticate("email", "password"); // this line throws 'Authentication Failed' exception.

    var emails = new List<Email>();
    for (int i = 0; i < 10; i++)
    {
        var message = emailClient.GetMessage(i);
        var emailMessage = new Email
        {
            Content = message.TextBody,
            Subject = message.Subject
        };
        emails.Add(emailMessage);
    }

    return emails;
}

Does anyone have any idea?

Answer 1

I know this sounds obvious, but the odds are that you're providing the wrong username and/or password. That's what the error is saying.

You can verify this by looking at the log file:

var emailClient = new Pop3Client(new ProtocolLogger("pop3.log"))

Maybe you can try creating a new Yahoo! Mail account that fails to authenticate just like your real account and give me the username/password for that new account so that I can debug the issue?

Does your username or password contain non-ASCII characters? How about punctuation characters?

If you want me to dig into this, I need to know what the username/password are and what MailKit is sending in case it's sending the wrong strings (pretty sure it's not, but I'll look into it anyway). If you don't give me that info, I can't diagnose the issue.