Fivetran: Syncs Are Intermittently Failing with "UNAUTHENTICATED: Token" Errors

Incident Report for Fivetran

Resolved

Incident Summary

Description:
We identified an issue where services were intermittently failing with the error:
"UNAUTHENTICATED: Token", resulting in connector sync failures during specific time windows.

Timeline:
This issue began on 2026-04-30 at 10:00 UTC and was resolved on 2026-04-30 at 16:30 UTC.
Customers might have experienced failures around scheduled deployment times (10:00, 13:00, and 16:00 UTC), with recovery shortly after.

Root Cause:
A recent internal change led to intermittent timeouts during authentication token validation, which triggered "UNAUTHENTICATED: Token" errors and caused some syncs to fail.

Resolution:
We implemented a fix to ensure sufficient time for token validation, preventing further sync failures.
All services are now operating normally.

Posted Apr 30, 2026 - 17:30 UTC