--- title: "New Feature: Proactive Queue Notifications | DuoCircle" description: "Today we are rolling out a much anticipated new feature to help manage and monitor your email flow more effectively, Proactive Queue Notifications." image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/blog/email-hosting/proactive-queue-notifications/" --- Quick Answer Proactive Queue Notifications send an email to the domain administrator (primary and secondary contacts in the client portal) when DuoCircle detects undelivered messages held past a threshold for a customer's mail servers. The most common causes are firewall rules that block our delivery IPs, mail-server-level blocking (greylisting, throttling, rate limits, blacklist/whitelist mismatches), local spam or virus scanning that is not whitelisting our sending IPs, or the mail server being down. Queued messages are retained for 30 days. The feature ships with Email Gateway and Backup MX. Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=undefined%2Fblog%2Femail-hosting%2Fproactive-queue-notifications%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=New%20Feature%3A%20Proactive%20Queue%20Notifications&url=undefined%2Fblog%2Femail-hosting%2Fproactive-queue-notifications%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=undefined%2Fblog%2Femail-hosting%2Fproactive-queue-notifications%2F "Share on Facebook") [ ](https://reddit.com/submit?url=undefined%2Fblog%2Femail-hosting%2Fproactive-queue-notifications%2F&title=New%20Feature%3A%20Proactive%20Queue%20Notifications "Share on Reddit") [ ](mailto:?subject=New%20Feature%3A%20Proactive%20Queue%20Notifications&body=Check out this article: undefined%2Fblog%2Femail-hosting%2Fproactive-queue-notifications%2F "Share via Email") ![Queue Notifications](https://media.mailhop.org/duocircle/images/2017/08/SPF-record-checker-8636.jpg) Today we are rolling out a much anticipated new feature to help manage and monitor your email flow more effectively, **Proactive Queue Notifications**. The **Proactive Queue Notifications** system sends an email to the domain administrator when we detect messages that have not been delivered to your servers within a predefined threshold. These notifications will provide you with information on how to remedy the alert and will be sent to both the primary and secondary email addresses that are configured in your client portal [https://portal.duocircle.com/clientarea.php?action=details](https://portal.duocircle.com/clientarea.php) The most common causes for queued messages is whitelisting or the firewalling of our delivery IP’s. Here is a very quick checklist to help you diagnose your issue. - **Whitelisting IPs on your Firewall** \- Your firewall rules do not include the EU servers ([click for IP listing](https://support.duocircle.com/solution/articles/5000524218-ip-addresses-for-firewalls)) [as outlined in this 2016 blog post.](/announcements/european-union-spam-filtering-goes-live/) - **Whitelisting IPs on the server** \- If your mail server supports whitelisting please update with the same IP’s as listed above. This is a different issue than firewall rules, as it is usually a rate limit or blacklist / whitelist on your mail server itself. Keywords: Greylisting, Whitelist, Throttle, Limit. - **Spam / Virus Scanning** \- Your mail server may have spam filter hosting configured locally in addition to the Spam / Virus filtering that we provide. If so, please whitelist our sending IP’s. - **Your mail server is down** \- In this case please ignore this message (if you have already made sure that our IP’s are in your firewall / whitelist) And we will continue to queue your messages until your server comes back online or 30 days. You can check the status of your messages by following these instructions: - The following services now include this enhancement: - Email Gateway - Backup MX **Our support is available 24/7 via chat, email or phone to help you resolve any delivery issues that you may be facing.** ![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) Brad Slavin General Manager General Manager at DuoCircle. Product strategy and commercial lead across the email security portfolio. ## Secure your email infrastructure Protect, authenticate, and deliver. Contact our team to find the right solution. [Contact Sales](/contact/) [Explore Products](/products/) ## Related Articles [ Email Hosting 18m 10 Steps To Set Up A Self-Hosted Mail Server Without Hitting Spam Mar 10, 2026 ](/blog/email-hosting/10-steps-set-up-self-hosted-mail-server-avoid-spam/)[ Email Hosting 5m The 9 Ways You Benefit from Moving Mail to the Cloud Apr 13, 2016 ](/blog/email-hosting/9-ways-benefit-moving-mail-cloud/)[ Email Hosting 1m Amazon Order Confirmation Trojan Feb 16, 2019 ](/blog/email-hosting/amazon-order-confirmation-trojan/)[ Email Hosting 6m Apache Log4j Zero-day Vulnerability: How to Detect it & Precautions You Need to Take Dec 24, 2021 ](/blog/email-hosting/apache-log4j-zero-day-vulnerability-how-to-detect-it-precautions-you-need-to-take/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. 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