Smartsheet change history: Investigating blank page or error on Smartsheet Login

Smartsheet’s major login incident caused intermittent blank pages or “upstream request timeout” errors, affecting Australia, Europe and the United States. It started at 2026-09-21 22:21 UTC and was resolved at 2026-09-22 03:43 UTC, lasting 5 h 21 min. Smartsheet attributed the issue to scheduled security maintenance on egress firewalls and confirmed login functionality was fully restored.