AdBook+ System Performance

On Friday, November 21, 2025, FatTail experienced a site-wide outage affecting client access to AdBook. Beginning at approximately 1:30PM ET, users were unable to log in to the platform. System access was restored by 2:00PM ET, resulting in an estimated 30-minute service disruption.

FatTail's alerting systems immediately identified the issue, prompting the Engineering and Client Success teams to take swift action. The FatTail status page was updated and direct client notifications were sent promptly to ensure transparency during the event.

Summary of Impact

Below is a detailed timeline of the outage:

• 1:30PM ET – Internal alerts notified FatTail of login failures within AdBook. Engineering immediately identified the cause of the issue and began working to restore the service.
• 2:00PM ET – The issue was fully resolved and all client access to AdBook was restored.

Root Cause

The outage was caused by an internal operator error. The engineering team was preparing for a planned maintenance window, and mistakenly issued a command on the production web server that caused the production system to go offline temporarily.

FatTail acknowledges this as a preventable error and is taking steps to strengthen operational safeguards.

Resolution

Engineering quickly isolated the cause of the outage and restored system functionality by 2:00PM ET. Services became available immediately upon restoration, and Client Success verified successful user login shortly after resolution.

Root cause validation and post-incident review began immediately following service restoration. Additional monitoring confirmed system stability and full functionality.

Remediation details will be added once Engineering completes their follow-up analysis.

Mitigation and Next Steps

FatTail is implementing additional safeguards to prevent this type of incident from recurring. The following actions will be taken:

Operational Safeguards for Production Access

• Implement environment isolation enhancements to reduce the risk of command execution in incorrect contexts.
• Introduce updated operational procedures for all team members with domain admin access.

Engineering Process Improvements

• Collaborate with Engineering leadership to define stricter access workflows.
• Evaluate tooling options to differentiate local vs. production environments through shell prompts, window themes, or command-line restrictions.
• Reinforce internal best practices and training for handling production-access tasks.