Email link tracking and short links were failing — resolved
Impact window: 17 Aug 2026, 11:47–13:01 UTC (1 h 13 min).
During this window, links in sent emails and SMS returned an error instead of resolving. This affected click tracking, open-tracking pixels, unsubscribe pages, web-version ("view in browser") links, and shortened links. Customers using their own branded sending domain were not affected.
Cause: a routine proxy upgrade at our edge began enforcing a TLS configuration check that had previously been ignored. A mismatch in our own routing configuration — harmless under the older version — caused the edge to reject these requests with HTTP 421 before they reached the tracking service.
Resolution: the routing configuration was corrected and all affected links resumed working at 13:01 UTC. We have audited every route on our edge for the same misconfiguration and fixed the remaining ones proactively.
Data note: requests rejected during the window never reached the tracking service, so click and open events for that period were not recorded and cannot be recovered retroactively. Message delivery itself was unaffected — emails and SMS were sent and received normally.
