What this error means

No module named 'proxy_server' is a LiteLLM failure pattern reported for developers trying to fix 'no module named proxy_server' error after updating litellm to 1.72.x. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

After updating to LiteLLM 1.72.7 or 1.72.8, proxy server fails with 'No module named proxy_server'. Workaround: pip install litellm[proxy]. Affects enterprise users running LiteLLM as AI gateway for 100+ LLM APIs.

Common causes

  • After updating LiteLLM to versions 1.72.7 or 1.72.8, users encounter 'No module named proxy_server' on startup and LiteLLM proxy crashes. Fix requires pip install litellm[proxy] but many users don't know this.
  • After updating to LiteLLM 1.72.7 or 1.72.8, proxy server fails with 'No module named proxy_server'. Workaround: pip install litellm[proxy]. Affects enterprise users running LiteLLM as AI gateway for 100+ LLM APIs.

Quick fixes

  1. Confirm the exact error signature matches No module named 'proxy_server'.
  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.