Call2Teams – Dynamic Emergency Trunk (DET) Service Degradation Across All Regions

Update timeline

1. investigating May 18, 2026, 10:38 AM UTC

   We are currently investigating a potential incident affecting Dynamic Emergency Trunk (DET) services for Call2Teams across all regions. Our teams are working to determine the scope and impact, and we will provide further updates every 60 minutes as more information becomes available. Thank you for your patience while we investigate. Dstny Support

2. investigating May 18, 2026, 11:48 AM UTC

   Engineering are continuing to investigate to determine the full impact, root cause, and an appropriate resolution. We will provide a further update in 60 minutes. Thank you for your patience. Dstny Support

3. investigating May 18, 2026, 12:36 PM UTC

   Service stability has improved following initial recovery actions, and we are now focusing on identifying and addressing the primary underlying cause. Engineering continue to work to determine the full impact and implement a resolution. We will provide a further update in 60 minutes. Dstny Support

4. monitoring May 18, 2026, 12:51 PM UTC

   Our Platform team has identified the root cause of the issue and implemented corrective measures to restore application services. We will continue to monitor service availability for the next 24 hours. and do not anticipate any further impact at this time. Thank you. Dstny Support.

5. resolved May 19, 2026, 01:40 PM UTC

   We are pleased to confirm that this incident has now been fully resolved. Over the past 24 hours, monitoring has shown no recurrence or further impact. The root cause has been identified, and measures have been implemented to prevent recurrence. A detailed post-mortem report will be shared within the next five business days. We apologise for any inconvenience caused and thank you for your patience and understanding. If you have any further questions, please contact our Support team. Thank you, Dstny Support

6. postmortem May 22, 2026, 02:26 PM UTC

   **Incident Summary** From 00:37 UTC on 17th May to 12:45 UTC on 18th May 2026, DET emergency trunk calling for Call2Teams was unavailable across all regions. The issue occurred following a host restart, which prevented network traffic from reaching the emergency trunks. While the service was impacted throughout this period, investigations confirmed that no customer emergency calls were attempted while the trunks were offline. Service was fully restored at 12:45 UTC on 18th May, with stability verified. **Root Cause** During an infrastructure restart, an automated system security service unintentionally activated and blocked essential network ports. This occurred due to a configuration oversight within the automation scripts and manual setup, which failed to ensure the service remained disabled upon reboot. This resulted in the emergency trunks being unable to establish the required network connections for call processing. **Incident Resolution** Engineering teams identified that the security service was active on the affected hosts and manually stopped the process. This immediately restored network connectivity, and all emergency trunks returned to a stable state. Final verification testing was completed at 12:45 UTC on 18th May, confirming that all regions were once again able to process emergency traffic correctly. **Mitigative Actions** * Permanently remove the conflicting security software from all relevant virtual machines to ensure they are reboot-safe. * Adjust call tester alerts and notification workflows to ensure faster escalation and investigation of availability warnings. * Improve internal logging and reporting for emergency trunk traffic to allow for more rapid impact assessment.