An array of emails waiting to be processed and delivered is known as an email queue. The sender and receiver are separated by a backlog of emails. Without being linked, they may still converse thanks to it. Step-by-step delivery of the emails begins when they have been enqueued.

How do Email Queues Work?

To transmit the message, the mail server works with the SMTP server. To transmit the email, the server communicates with Mail servers on the domains of the recipient. The majority of mail servers handle the actual sending using a mail transfer agent (MTA) named sendmail.

The MTA will send each message in the queue as it is finished periodically. In the event that the recipient's SMTP server is unresponsive, sendmail will continue to send emails. Typically, this kind of issue will be reported to your mail client. The email will be rejected if the sendmail queue is unable to deliver it within a certain time frame .

Difference Between Smtp Server, And Mail Transfer Agent

A computer that employs email protocols to deliver and receive electronic communications is known as a mail server. The component of the mail server that manages outgoing mail is known as an SMTP server. A special kind of software called a mail transfer agent, or MTA, queues email and pushes it up the delivery cycle till it reaches a mail delivery agent (MDA).

How To Fix Clogged Email Queue?

The SMTP server appends your outgoing emails to an email queue when you're bulk mailing. On the other hand time, queued emails might become a problem if they take an exceptionally long time to send. Emails in the queue won't come back. Even though they will still be delivered, the delivery time might be drastically shortened.

Increased Email Volume

Some email service providers impose IP address-based email rate limitations. The delivery time will drop if you went beyond this pace and queue an excessive number of emails. Additionally, you can exceed the limit for email attachment volume, which could be a hindrance. The only option is to repeatedly push the queue by contacting the incoming server.

Spamming Issues

Your email queue may occasionally get backed up by spam filters. Filter will permit the emails to flow so that it may assess how the other recipients respond to the communication. There may be a number of causes for it to be stuck, including the blocking of your IP address. You should remove yourself from this list and improve your email marketing strategy.

Email Queue In Your Application

An email queue can be necessary if your application monitors monthly megabytes and you intend to send a message after 70 to 90 percent of that amount has been used. You should choose a sophisticated email sending architecture if you send more than 10,000 commercial or bulk emails every day. It bases sending emails on an asynchronous mechanism that queues messages before they get to the mail server.

Check Your Email Queuing System

You may send emails to and via your app using a fake SMTP server. This prevents any problems brought on by incorrect configuration, authentication, and other factors. Your business or advertising emails will be sent to a fake POP3 server, preventing spam from reaching actual users. You'll eventually receive your email in the Demo folder if your app runs well.


The sending and receiving of emails are separated by email and SMTP queuing. This is helpful in circumstances involving bulk or mass mailing, but it may also be linked to a problem that causes the message to be sent later than expected. You now know how to address these issues and make the most of email queuing at the same time.