POST SMTP Mailer – Email log, Delivery Failure Notifications, Chrome and Slack Support, Connect with any SMTP, including Gmail, Outlook, SendinBlue, Sendgrid, Mailgun, Zoho, SES, and More.. It was authored by Post SMTP. It currently has around 359 starts, 55 support threads and 44 support thread resolved, 6,584,650 downloaded and installed by 300,000 users.