[Bug]: Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names

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

1. Confirm the exact error signature matches Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names.
2. Check the LiteLLM account, local tool state, and provider configuration involved in the failing workflow.
3. 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

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. 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.

Sources checked

• https://github.com/BerriAI/litellm/issues/28019

Evidence note: 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.

Related errors

• LiteLLM

FAQ

What should I check first?

Start with the exact Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed LiteLLM workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without Fallback lookup fails for team-scoped models — model_group uses public name but fallback config requires internal names.