Throttling means the intentional delay in email delivery rate. This delay can occur due to a few specific reasons and the emails get throttled at a few places.

When And Where The Email Throttling Occurs?

The electronic mail was created on August 30, 1982. It was created in New Jersey by Shiva Ayyaduari, a worker at the University of Medicine and Dentistry. Shiva produced more than 50,000 lines of code during his tenure there. He was the first to create a comprehensive electronic model of the cooperative email system, which includes elements like an Inbox, Outbox, Folder, and many more features.

Between Sender And Recipient Systems

An SMTP Relay, HTTP API, and user interface for sending emails are all included in Elastic Email, a comprehensive email delivery platform. We restrict each account to a maximum of 20 simultaneous connections for both SMTP and API submissions in order to prevent one user from dominating both servers. We also suggest setting any connection timeout settings to a minimum of 30 seconds.

Throttling of elastic email systems

Every email that leaves our servers is under the watchful eye of Elastic Email, and we keep track of the answers we get from the servers of the recipients. We will slow down if they signal that we should and stop if they want us to. Finally, how the recipient's server interprets your letter determines both our reputation as an email provider and your reputation as an email sender.

Throttling of recipient servers

Have you received emails that are marked as:

  • In Progress
  • Waiting To Retry
  • Throttled
  • Not Delivered

This might be a sign that the receiver server is throttling the delivery speeds. The receiver server can deal with this in a number of ways. Connections could be postponed or accepted but on a greylist.

Reasons my email being throttled?

Usually, Elastic Email and receiver servers impose email throttling for similar reasons. Your email could also be throttled by Elastic Email if recipient servers do the same.

Abuse Reports

Your email may not be delivered if your contacts complain about it or report it. Both recipient servers and Elastic Email have a very low tolerance for abuse reports. If your email is inappropriate, does not have a working action button, or is not double-opted-in, it may be throttled.

Email sent to outdated email addresses

Don't send an email to email addresses if you haven't sent mail to them for more than 1 year. If you send emails to old, inactive email addresses, even if they signed up for your service, they may now be spam traps. This can get our IP blacklisted and will definitely lead to the throttling of your mail.

Sending unformatted material

Make sure to transmit your materials once they have been spam-checked. This is especially important if your line of work involves anything related to rental housing, mortgage loans, sports, or sponsored links, all of which are recognized for having high levels of spam.


If your email is unformatted or contains unauthorized content then it will not be sent. Unsolicited emails are also kept in a queue. For a maximum of 2 days, the Elastic Email System will try to deliver your email. Your letter will be taken out of the queue if we are unable to deliver it within 2 days. For undeliverable mail, reimbursement is not available. You might need to switch email providers or set up your own email services if you are being throttled.

Many of those who are throttled had no idea they were doing anything incorrectly. Feel free to resume sending. Our system is extremely responsive, and your email will begin to flow quickly almost instantly. The Throttle Warning may vanish if you have successfully sent at least a million emails with no abuse reports or too many failures.