On April 16, 2025, at 18:15 UTC, users started to encounter difficulties logging into the Anaplan platform. During the incident, users may have struggled to log in and/or received an error message "431 - Header too large" when using the platform. This impacted users in us3: Anaplan Google Cloud-Dedicated.
Our investigation found that the issue related to a configuration change that had been made to an authentication component earlier that day. We performed a comprehensive rollback and completed a rolling restart of the impacted service to restore stability. Additionally, we advised affected customers to clear their browsing data. Full service was restored at 20:50 UTC.
Following this incident, we've initiated a thorough review of our pre- and post-release testing procedures. We’re also optimizing our authentication service to enable self-recovery. These enhancements to our release process will help us identify issues earlier and address them as soon as possible.
We apologize for any impact this might have had on your business operations. We’re continuously strengthening our systems and procedures to ensure we avoid future disruption to your business and users.
If you have further questions or concerns, please visit our Support website. Thank you for your patience during this situation and thank you for being an Anaplan customer.