Proton Says Massive Outage Caused by Infrastructure Overload

Proton has attributed yesterday's widespread service outage to an unexpected overload in its infrastructure during a critical migration phase. The incident, which lasted for several hours, primarily impacted Proton Mail and Proton Calendar, leaving many users experiencing intermittent access to these services.

The outage began around 4:00 PM Zurich time when the number of database connections surged globally, overwhelming Proton's systems. While other services like Proton VPN, Proton Pass, and Proton Drive were restored swiftly, Proton Mail faced prolonged issues due to its ongoing migration to a Kubernetes-based infrastructure.

Proton explained that the outage was exacerbated by its migration to a new infrastructure. This process, intended to improve scalability and resilience, temporarily required Proton to run two parallel systems, limiting its ability to redirect traffic effectively. Since Proton Mail had not yet fully migrated, it was particularly vulnerable to the sudden spike in load.

A subsequent investigation identified a software change as the likely trigger for the load spike. Although this change had been implemented earlier without immediate issues, its effects materialized unexpectedly, leading to a surge in database connections. Once the change was rolled back, traffic returned to normal levels.

Proton improves resilience

Proton acknowledged the challenges posed by the migration and emphasized its commitment to completing the process as quickly as possible. The company noted that the fully migrated Kubernetes-based infrastructure will provide greater redundancy and enable it to handle unexpected incidents with less disruption.

In a statement, Proton apologized for the inconvenience caused by the outage and assured users that a post-mortem analysis is underway to prevent similar issues. The incident also highlighted the complexity of infrastructure transitions and the trade-offs involved in ensuring long-term improvements.

Proton Mail and Calendar are core services for the company's privacy-focused user base, which includes professionals, organizations, and individuals prioritizing secure communications. The outage highlighted the importance of reliability in critical services, particularly for a platform that markets itself as a privacy-first alternative to mainstream providers.

Regarding rumors of a cyberattack or compromise on Proton's infrastructure by hackers that circulated online yesterday, given the available evidence and the company's update, these are unfounded.