Service Incident - July 9, 2026 - Support | All Pods - Side Conversation PDF Attachments Failing to Load

Summary

On July 9, 2026, from 11:59 UTC to 16:49 UTC, some customers were unable to open PDF attachments from Side Conversations in Agent Workspace, and saw the error message “Failed to load PDF attachment.”

Timeline

July 09, 2026 12:13 PM
Between 11:59 - 16:49 UTC on July 9th some customers experienced issues accessing attachments on side conversations, resulting in the error message “Failed to load PDF attachment”. We have since reverted the change and attachments are now accessible as expected. We apologize for the disruption this caused.

Customer impact

Who was affected: Some Support customers using Side Conversations in Agent Workspace (across multiple pods).

What happened: The PDF viewer could spin and then fail with “Failed to load PDF attachment.”

When: Approximately 11:59 UTC to 16:49 UTC on July 9, 2026.

What was not impacted: Other (non-PDF) attachments continued to work as expected.

Data loss / exposure: None.

Root cause

A change deployed to our Side Conversations attachment handling introduced an unintended behavior change for PDF downloads.

Specifically, part of the update that was intended to be controlled behind a feature flag was not fully gated, so the change affected more traffic than intended. That caused the PDF download/streaming flow to break in production, resulting in PDFs failing to load in the Agent Workspace viewer.

Mitigation and recovery

We reverted the change at 16:49 UTC, which restored normal PDF attachment loading.

What we’re doing to prevent this in the future

Ensure the full PDF-handling change is completely gated behind the feature flag (so behavior changes are atomic and can’t partially apply).

Add automated test coverage to validate both “flag on” and “flag off” behavior.

Strengthen pre-production validation to test the full end-to-end behavior in staging for both flag states.

Improve monitoring/alerting on the attachment download path so regressions are detected faster.

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.