ServiceNow has resolved this issue on Friday, August 28, 2026 with a maintenance patch. The problem was related to an issue in the ServiceNow patch identified in their article KB3147727 (https://support.servicenow.com/kb_view.do?sysparm_article=KB3147727)

We recommend that customers who have integrated ServiceNow with xMatters hold off on installing the following ServiceNow patch until further notice: Zurich Patch 10 Hotfix 4 Build tag: glide-zurich-07-01-2025__patch10-hotfix4aw34-08-16-2026 We have observed that this patch may disrupt communication between ServiceNow and xMatters. Our teams are actively investigating the issue and working to determine the appropriate resolution. If you have already installed the patch and are experiencing integration issues, rolling back the patch has been shown to restore normal operation. Please contact xMatters Support if you need further assistance. We will provide another update when more information is available. We apologize for any inconvenience.