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
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) as outlined in this 2016 blog post.
- 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 / Virus filtering 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 10 days.
You can check the status of your messages by following these instructions:
The following services now include this enhancement:
- Email Gateway
- Backup MX