EU - Incident with Copilot GPT-5.1-Codex

Update timeline

1. investigating Feb 20, 2026, 10:02 AM UTC

   We are investigating reports of degraded performance for Copilot

2. investigating Feb 20, 2026, 10:02 AM UTC

   We are experiencing degraded availability for the GPT 5.1 Codex model in Copilot Chat, VS Code and other Copilot products. This is due to an issue with an upstream model provider. We are working with them to resolve the issue. Other models are available and working as expected.

3. investigating Feb 20, 2026, 10:36 AM UTC

   We are still experiencing degraded availability for the GPT 5.1 Codex model in Copilot Chat, VS Code and other Copilot products. This is due to an issue with an upstream model provider. We are working with them to resolve the issue.

4. investigating Feb 20, 2026, 11:19 AM UTC

   The issues with our upstream model provider have been resolved, and GPT 5.1 Codex is once again available in Copilot Chat and across IDE integrations [VSCode, Visual Studio, JetBrains]. We will continue monitoring to ensure stability, but mitigation is complete.

5. resolved Feb 20, 2026, 11:41 AM UTC

   On February 20, 2026, between 07:30 UTC and 11:21 UTC, the Copilot service experienced a degradation of the GPT 5.1 Codex model. During this time period, users encountered a 4.5% error rate when using this model. No other models were impacted. The issue was resolved by a mitigation put in place by the external model provider. GitHub is working with the external model provider to further improve the resiliency of the service to prevent similar incidents in the future.