A cooling failure in Proton's Frankfurt datacenter took most Proton services offline

Sources: Proton status, incident kzklhrdg6hxp
Summary: Proton's status page reports a cooling failure in its Frankfurt datacenter that took Mail, Drive, Pass, Calendar, Wallet, SimpleLogin, and Lumo by Proton offline. Proton downgraded VPN to a partial outage in a 00:18 CEST update, reporting that it worked for some users. Proton identified the cooling failure at 00:38 CEST, recovered through traffic failover onto backup sites, and marked the incident resolved at 02:27 CEST on 2026-08-27 with services back online and the remaining minor issues cleared, stating no data was lost and a post mortem will follow.
Why it matters: The failure mode was physical cooling rather than software, so no code rollback applied and recovery depended entirely on the failover path.