Outage in Cornerstone

Spamhaus Temporarily Blacklisted UK Email IP

Major
October 06, 2025 - Started 6 days ago
Official incident page

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Outage Details

Cornerstone UK email sending IPs have been temporarily blacklisted by Spamhaus, a leading global email reputation authority, due to poor email hygiene detected in email activity originating from certain customer accounts. During this time, emails may fail to deliver. This is our top priority and we are working closely with the vendor to resolve the problem as soon as possible. Please check back periodically for additional updates, which will be posted as they become available.
Latest Updates ( sorted recent to last )
MONITORING about 8 hours ago - at 10/12/2025 11:04AM

Our monitoring confirms that email delivery has remained fully stable since the IP configuration change on October 10th. No new delivery failures have been observed due to the Spamhaus blacklisting, and all emails are being successfully delivered.

Everything continues to look good at this time. We are continuing to monitor the system and will provide another update within the next 24 hours as we complete the 48-hour observation window.

MONITORING about 8 hours ago - at 10/12/2025 11:03AM

Email delivery remains stable following the IP configuration change on October 10th. No new delivery failures have been detected, and all emails continue to be successfully delivered.

We will continue to monitor the situation closely and provide an update after 24 hours.

MONITORING 1 day ago - at 10/11/2025 11:01AM

Our monitoring confirms that email delivery has remained fully stable since the IP configuration change on October 10th. No new delivery failures have been observed due to Spamhaus blacklisting, and emails are being successfully delivered.

Everything continues to look good at this time. We will continue to monitor until the 48-hour window is complete. We will update you again in the next 24 hours.

MONITORING 2 days ago - at 10/10/2025 10:57AM

The CSOD Technology Team has successfully updated our email configuration to route traffic through an IP address in good standing. Beginning at 1200 AM Pacific Time on October 10th, UK Swimlane customers should no longer experience issues with email delivery due to Spamhaus blacklisting. All emails from Cornerstone are now expected to be delivered successfully.

We will continue to closely monitor the situation for the next 48 hours before closing this incident.

Background:
The email delivery disruption affecting UK Swimlane customers was due to our primary email IP being blacklisted by Spamhaus, starting at approximately 3:30 PM Pacific Time on October 6th. During this period, some customers may have experienced intermittent email delivery failures, depending on their organization’s IT security policies.

We appreciate your patience and will provide further updates as needed.

IDENTIFIED 2 days ago - at 10/10/2025 10:47AM

We remain in contact with Spamhaus while awaiting confirmation of the delisting. Further updates will be provided in due course.

IDENTIFIED 2 days ago - at 10/10/2025 08:41AM

We remain in contact with Spamhaus while awaiting confirmation of the delisting. Further updates will be provided in due course.

IDENTIFIED 3 days ago - at 10/10/2025 06:11AM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.

IDENTIFIED 3 days ago - at 10/10/2025 04:06AM

We remain in contact with Spamhaus while awaiting confirmation of the delisting. Further updates will be provided in due course.

IDENTIFIED 3 days ago - at 10/10/2025 02:11AM

We remain in contact with Spamhaus while awaiting confirmation of the delisting. Further updates will be provided in due course.

IDENTIFIED 3 days ago - at 10/09/2025 11:02PM

Communication with Spamhaus is ongoing as we await confirmation of the delisting request. We will continue to share updates on a regular basis.

IDENTIFIED 3 days ago - at 10/09/2025 08:31PM

Communication with Spamhaus is ongoing as we await confirmation of the delisting request. We will continue to share updates on a regular basis.

IDENTIFIED 3 days ago - at 10/09/2025 04:12PM

We’re actively engaging with SpamHaus and still waiting for their reply regarding our delisting request. The next update will be provided in 4 hours or sooner if any feedback from SpamHouse is available before that time.

IDENTIFIED 3 days ago - at 10/09/2025 12:03PM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. The next update will be provided in 4 hours or sooner if any feedback from SpamHouse is available before that time.

IDENTIFIED 3 days ago - at 10/09/2025 09:45AM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.

IDENTIFIED 4 days ago - at 10/09/2025 07:01AM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.

IDENTIFIED 4 days ago - at 10/09/2025 04:39AM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.

IDENTIFIED 4 days ago - at 10/09/2025 02:41AM

We’re actively engaging with SpamHaus and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.

IDENTIFIED 4 days ago - at 10/09/2025 12:40AM

We are in ongoing communication with SpamHaus and are currently awaiting their response to our delisting request. We’ll continue to provide regular updates until the issue is fully resolved.

IDENTIFIED 4 days ago - at 10/08/2025 10:44PM

We continue to communicate with SpamHaus and are awaiting a response to our delisting request. Regular updates will be shared until this is resolved.

IDENTIFIED 4 days ago - at 10/08/2025 08:33PM

We are in ongoing communication with Spamhaus and awaiting confirmation of our delisting request. We will continue to provide regular updates until this is resolved.

IDENTIFIED 4 days ago - at 10/08/2025 05:00PM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 4 days ago - at 10/08/2025 03:03PM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 4 days ago - at 10/08/2025 12:47PM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 4 days ago - at 10/08/2025 09:07AM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/08/2025 07:07AM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/08/2025 05:01AM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/08/2025 03:08AM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/08/2025 01:00AM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/07/2025 11:01PM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/07/2025 08:56PM

We continue to work closely with Spamhaus as we await confirmation of our delisting request. We will share regular updates as new information becomes available.

IDENTIFIED 5 days ago - at 10/07/2025 07:00PM

We are still awaiting a response from Spamhaus regarding the delisting request and will provide an update as soon as we receive any information.

IDENTIFIED 5 days ago - at 10/07/2025 02:55PM

We are currently awaiting a response from Spamhaus regarding the delisting request and will provide an update as soon as we receive any information.

IDENTIFIED 5 days ago - at 10/07/2025 11:45AM

Cornerstone IPs remain listed on the Spamhaus blocklist, which means email deliveries may continue to be impacted, depending on the client’s Domain Reputation Checker policies for Spamhaus.
We are still awaiting further updates from Spamhaus regarding the delisting request.

IDENTIFIED 5 days ago - at 10/07/2025 09:35AM

We are currently awaiting a response from Spamhaus regarding the delisting request and will provide an update as soon as we receive any information.

IDENTIFIED 5 days ago - at 10/07/2025 07:36AM

We are continuing to work on the fix for this issue.
The next update will follow within 2 hours or as soon as we receive further information.

IDENTIFIED 6 days ago - at 10/07/2025 05:31AM

Email delivery success rate is improving. We will update you further in the next two hours.

IDENTIFIED 6 days ago - at 10/07/2025 03:39AM

We have identified the cause of the issue and have implemented internal corrective measures. We are working to restore normal operations. We will update you further in the next two hours.

INVESTIGATING 6 days ago - at 10/07/2025 01:35AM

We are continuing to investigate this issue as our top priority and will provide regular updates until it is fully resolved. Thank you for your continued patience and understanding.

INVESTIGATING 6 days ago - at 10/06/2025 11:49PM

Cornerstone UK email sending IPs have been temporarily blacklisted by Spamhaus, a leading global email reputation authority, due to poor email hygiene detected in email activity originating from certain customer accounts.

During this time, emails may fail to deliver. This is our top priority and we are working closely with the vendor to resolve the problem as soon as possible. Please check back periodically for additional updates, which will be posted as they become available.

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