**Summary** Google Chat users might not be able to open chat while connecting from Europe. **Description** We are experiencing an issue with Google Chat beginni...

What caused it: Google Chat's root cause analysis

# Incident Report Summary On Monday, 24 November 2025, Google Chat experienced an overload which led to service disruptions for users for a duration of 1 hour and 53 minutes. Customers encountered issues including the inability to send messages, load the chat application, and start new conversations. Some notifications were also incorrectly displayed with "Anonymous" as the sender. We deeply regret the disruption our Google Workspace customers experienced. We are committed to improving our platform's reliability and performance, and we are taking immediate steps to improve the platform’s performance and availability. Root Cause The trigger of the outage was transient errors served from an internal microservice in Europe that caused Chat backend processes to execute a fallback path to retrieve this data. The root cause was that the data retrieved from the fallback path subsequently caused an update to Chat metadata which were sent to user devices, causing those devices to reload data from Chat backend servers, thereby causing more updates to be sent to user devices resulting in a cascading effect that overloaded Chat servers in Europe. Google engineers have implemented a mitigation to limit high rates of requests to prevent this cascading loop from recurring. Remediation and Prevention Google engineers were alerted to the incident via alerts and immediately started an investigation. To fully mitigate the impact, our engineering teams took the following steps: 1. Increased Server Capacity: To handle the unexpected surge in traffic, we significantly increased the capacity of our servers in the affected region to ensure the system could process all incoming requests smoothly. 2. Limited the Rate of Metadata Updates: To prevent the cascading loop of requests from overloading Chat servers again, Google engineers have limited the rate of metadata updates so that Chat servers will not be overloaded in this way. 3. Paused Non-Essential Background Tasks: To prioritize the restoration of core chat functions, we temporarily halted several internal background processes. This action helped to reduce the overall load on our systems, freeing up resources to serve user traffic more effectively. 4. Gradual Traffic Restoration: Our automated defenses had initially blocked some traffic to prevent a complete system overload. A crucial part of the recovery was to gradually and carefully allow this traffic back. This controlled approach ensured that as users reconnected, the sys...

Read the full postmortem from Google Chat