MailKit very slow to send SMTP

Question

I used SendGrid earlier to send emails on my ASP.net Core project and it was very fast but costly due to heavy load. I currently have an Office 365 account and I can use the SMTP server so I decided to use MailKit. The email gets sent successfully but it takes a very long time although I'm awaiting the call... The following is the code I use:

    public async Task SendEmailAsync(string email, string subject, string message)
    {
        var emailMessage = new MimeMessage();
        emailMessage.From.Add(new MailboxAddress("name", "name@domain.com"));
        emailMessage.To.Add(new MailboxAddress(email));
        emailMessage.Subject = subject;
        emailMessage.Body = new TextPart("Html") { Text = message };

        using (var client = new SmtpClient())
        {
            await client.ConnectAsync("smtp.office365.com", 587, SecureSocketOptions.Auto).ConfigureAwait(false);
            await client.AuthenticateAsync("*******", "******");
            await client.SendAsync(emailMessage).ConfigureAwait(false);
            await client.DisconnectAsync(true).ConfigureAwait(false);
        }
    }

I have seen the suggestion in this question: MailKit SMTP slow when sending messages and I applied it but the problem still happens.

Thank you

@jstedfast Please see my answer below, thank you so much for your care. — Techy, Jan 23 '17 at 21:31
If you have Office365 consider using the Microsoft Graph API. It's meant to do that... this will only work if you are using your Office365 account for auth. Check graph.microsoft.io for the docs. — Patrick Mcvay, Jan 27 '17 at 20:10

score 0 · Accepted Answer · answered Jan 23 '17 at 21:31

0

I have contacted Microsoft and I was told that they're facing problems with Office 365 and has been reported by many. This is not a server downtime issue, I wish I was told that before signing up!

answered Jan 23 '17 at 21:31

Techy

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MailKit very slow to send SMTP

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