Service Incident - March 23, 2026 - Support | Pod 23 - Increased 5XX errors when logging in to Zendesk accounts

Summary

On March 23, 2026, between 18:51 and 19:54 UTC, multiple customers from Pod 23 reported issues with getting increased 5XX errors when signing into Zendesk. Problems included slow or unresponsive sign-in pages and temporary sign-in failures or timeouts, with many customers able to access service after retrying during recovery.

Timeline

March 23, 2026 19:57 UTC | March 23, 2026 12:57 PM PT

We are aware of an issue impacting some customers on pod 23 preventing the login screen from loading. We are actively working on a solution and will provide updates as they become available.

March 23, 2026 20:06 UTC | March 23, 2026 01:06 PM PT

Our engineering teams have applied a change and are monitoring the results, we are now observing a return to normal error rates and users should now be able to access the login page without further issues. Please let us know if you continue to experience any issues with your agents or end-users accessing the sign in page.

March 23, 2026 20:06 UTC | March 23, 2026 01:06 PM PT

After monitoring we are confident that we have observed full recovery after the issue impacting sign in pages on pod 23. Please reach out if you have any further issues or questions.

Root Cause Analysis

The incident was caused by an unusually high volume of automated traffic targeting the Zendesk sign-in page of a single customer site. This surge consumed shared sign-in resources, leading to cascading failures and timeouts affecting multiple customers on the same infrastructure group.

Resolution

The issue was resolved by challenging and blocking abusive traffic, which restored healthy system capacity and normalized sign-in behavior. Moving forward, we are focusing on faster detection and response to similar traffic surges and strengthening our automatic scaling to ensure service availability during unexpected high load periods.

Remediation Items

Ensure the login system automatically handles increased traffic during busy periods.

Improve alerts to detect and respond to attacks sooner.

Perform regular tests to make sure the sign-in page can manage high traffic.

Implement general limits on sign-ins to reduce overload.

Coordinate with our partner provider to enhance protection against attacks.

Keep the ‘Survive the Ark’ customer updated about the incident and the steps we're taking.

FOR MORE INFORMATION

For current system status information about Zendesk and specific impacts to your account, visit our system status page. If you have additional questions about this incident, contact Zendesk customer support.