What this error means
Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names is a LiteLLM failure pattern reported for developers trying to fix litellm proxy fallback configuration not working for team-scoped byok models due to public vs internal model name mismatch. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
GitHub issue #28019 in BerriAI/litellm (opened May 15, 2026). When a team-scoped BYOK model has a fallback configured via POST /fallback (which requires internal model names like model_name_team_uuid), requests using the public model name fail to trigger fallback routing. Router.async_function_with_fallbacks reads the unresolved public name before resolution, causing direct string comparison to never match.
Common causes
- GitHub issue #28019 in BerriAI/litellm (opened May 15, 2026). When a team-scoped BYOK model has a fallback configured via POST /fallback (which requires internal model names like model_name_team_uuid), requests using the public model name fail to trigger fallback routing. Router.async_function_with_fallbacks reads the unresolved public name before resolution, causing direct string comparison to never match.
Quick fixes
- Confirm the exact error signature matches
Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names. - Check the LiteLLM account, local tool state, and provider configuration involved in the failing workflow.
- Compare the failing environment with a known working setup, then change one configuration value at a time.
Platform/tool-specific checks
- Verify the command, editor, extension, or API client that produced the error.
- Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
- Avoid deleting credentials, local model data, or project settings until the failing scope is clear.
Step-by-step troubleshooting
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- Keep the working fix documented for the team or deployment environment.
How to prevent it
- Keep provider/tool configuration documented.
- Record non-secret diagnostics such as tool version, provider name, model name, and command path.
- Add a lightweight check before CI or production workflows depend on the tool.