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Smartsheet: 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.
Machine-written from the archived incident (Sol). Check the timeline before relying on it.
Affected components: Core Application - Smartsheet LoginSmartsheet Login
Timeline of updates
- investigating
We are investigating an issue where some customers encounter an intermittent blank page or the error "upstream request timeout" attempting to access the Smartsheet Login page at app.smartsheet.com. Our team is fully engaged in addressing the situation. We will provide frequent updates until we reach a monitoring status.
- monitoring
We are observing stability being restored for Smartsheet Login. We are continuing to monitor it closely to confirm full service stability. We will provide frequent updates until we reach a resolved status.
- resolved
Smartsheet Login functionality has been fully restored and is operating normally. The incident is now resolved.
- postmortem
On September 21, 2026, Smartsheet experienced intermittent login page loading issues across three regions between 11:42 AM and 3:30 PM PDT, impacting Australia from 11:42 AM to 12:34 PM PDT, Europe from 2:05 PM to 3:00 PM PDT, and the United States from 2:05 PM to 3:30 PM PDT. The issue was triggered during scheduled security maintenance on egress firewalls, where default load balancer routing maintained long-lived proxy connections to rebooting appliances rather than resetting and redirecting them immediately to healthy instances. Consequently, approximately 12% to 20% of users attempting to load the login page during these regional windows experienced intermittent timeouts, while existing authenticated user sessions remained unaffected and no data integrity was compromised. Service fully recovered across all regions by 3:30 PM PDT as connections refreshed, and automated TCP connection-reset configurations are being enabled on load balancers to ensure seamless failover during any future appliance maintenance.
Rewindex changes for this incident
- Major incident: Investigating blank page or error on Smartsheet Login 2026-09-21 22:21 UTC
Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab). Smartsheet profile · Recent Smartsheet incidents · Markdown · JSON