A broad set of users lost access to OpenAI's primary chatbot on Sept 30, hours after the company had cleared its previous backlog of errors. This renewed outage began around 21:36 UTC, rendering ChatGPT inaccessible for many users across the platform.

The failures follow a brief window of stability at 10:43 UTC on Sept 30, when OpenAI confirmed that services for Pro and Plus subscribers had recovered. The overall instability began on Sept 29, during which the company investigated elevated error rates that impacted both ChatGPT and the Codex model.