Cornerstone incident
Mailspike Temporarily Blacklisted UK Email IP
Cornerstone experienced a minor incident on July 8, 2026 affecting Uptime and Uptime and 1 more component, lasting 2d 1h. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Jul 08, 2026, 02:17 PM UTC
Cornerstone UK's email sending IPs have been temporarily blacklisted by Mailspike, a community-oriented IP reputation authority, due to a high number of email delivery failures 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.
- investigating Jul 08, 2026, 04:16 PM UTC
We’re actively engaging with Mailspike and awaiting their reply regarding our delisting request. Regular updates will be provided until the matter is completely resolved.
- investigating Jul 08, 2026, 07:19 PM UTC
We remain in contact with Mailspike while awaiting confirmation of the delisting. Further updates will be provided in due course.
- investigating Jul 08, 2026, 10:21 PM UTC
We remain actively engaged with the vendor and are awaiting confirmation on the delisting. We will continue sharing updates as they become available.
- investigating Jul 09, 2026, 12:22 AM UTC
We remain actively engaged with the vendor and are awaiting confirmation on the delisting. We will continue sharing updates as they become available.
- investigating Jul 09, 2026, 02:23 AM UTC
We remain actively engaged with the vendor and are awaiting confirmation on the delisting. We will continue sharing updates as they become available.
- investigating Jul 09, 2026, 05:19 AM UTC
We are continuing to work closely with the vendor to obtain confirmation on the IP delisting request. We will provide the next update as soon as we receive any new information.
- investigating Jul 09, 2026, 06:58 AM UTC
Cornerstone UK's email sending IPs have been temporarily blacklisted by Mailspike, a community-oriented IP reputation authority, due to a high number of email delivery failures 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.
- investigating Jul 09, 2026, 09:06 AM UTC
We are continuing to work closely with the vendor to obtain confirmation on the IP delisting request. We will provide the next update as soon as we receive any new information.
- investigating Jul 09, 2026, 03:53 PM UTC
We are continuing to work closely with the vendor to obtain confirmation on the IP delisting request. We will provide the next update as soon as we receive any new information.
- resolved Jul 10, 2026, 04:08 PM UTC
After careful review and monitoring, we’ve determined this does not meet the definition of a Severity2: emails are firing as expected, and Mailspike’s blacklisting is having only a minor effect on email delivery for customers in the impacted IP—primarily those who rely on Mailspike for inbound email filtering. As a result, the incident is being closed on the Status page, and any further communications will be handled as a Severity3 via the existing Known Issue article: https://cornerstoneondemand.my.site.com/s/articles/Known-Issue-CSX-UK-Email-IP-blacklisted-by-Mailspike CSOD technical teams will continue working closely with Mailspike to address the underlying concerns.