Incident with Copilot
Nov 28, 06:59 UTCNov 28, 08:23 UTC
Duration
1h 24m
Impact
Major
Root cause
Config change
GitHub, 90 days
68 incidents
Affected
Not listed by the vendor.
Final update
On November 28th, 2025, between approximately 05:51 and 08:04 UTC, Copilot experienced an outage affecting the Claude Sonnet 4.5 model. Users attempting to use this model received an HTTP 400 error, resulting in 4.6% of total chat requests during this timeframe failing. Other models were not impacted. The issue was caused by a misconfiguration deployed to an internal service which made Claude Sonnet 4.5 unavailable. The problem was identified and mitigated by reverting the change. GitHub is working to improve cross-service deploy safeguards and monitoring to prevent similar incidents in the future.
Timeline
- Resolved · Nov 28, 08:23 UTC
On November 28th, 2025, between approximately 05:51 and 08:04 UTC, Copilot experienced an outage affecting the Claude Sonnet 4.5 model. Users attempting to use this model received an HTTP 400 error, resulting in 4.6% of total chat requests during this timeframe failing. Other models were not impacted. The issue was caused by a misconfiguration deployed to an internal service which made Claude Sonnet 4.5 unavailable. The problem was identified and mitigated by reverting the change. GitHub is working to improve cross-service deploy safeguards and monitoring to prevent similar incidents in the future.
More from GitHub
Full history| Started | Incident | Impact | Duration |
|---|---|---|---|
| Sep 2310:11 UTC | Incident across several services | minor | Ongoing |
| Sep 2022:13 UTC | Incident with Pull Requests | minor | 1h 9m |
| Sep 1720:59 UTC | Elevated rate of errors for OpenAI models provided by Copilot | minor | 50m |
| Sep 1607:20 UTC | Degradation with Gemini 3.8 Flash | major | 10h 28m |
| Sep 1519:11 UTC | Disruption with some GitHub services | minor | 49m |
| Sep 1509:47 UTC | Disruption with some GitHub services | minor | 1h 30m |
Also caused by configuration change
All| Started | Vendor | Incident | Impact | Duration |
|---|---|---|---|---|
| Sep 2218:20 UTC |  Twilio | Phone Number APIs and Console Were Returning Incorrect 404 ResponsesTwilio | none | 0m |
| Sep 1622:30 UTC |  Cloudflare | Hyperdrive Elevated Origin Connection Failure RatesCloudflare | none | 0m |
| Sep 1211:04 UTC |  Slack | Some customers experiencing blurry image previews and download issuesSlack | minor | 8h 56m |
| Sep 1107:18 UTC |  Snowflake | INC20000213Snowflake | critical | 6h 1m |
| Sep 407:34 UTC | Snowflake | INC20000199Snowflake | critical | 2h 36m |
| Sep 109:58 UTC | Snowflake | INC20000190Snowflake | major | 3h 52m |
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