BerriAI/litellm · error · Exception

Authentication failed. Check your Arize Phoenix API key and

Error message

Authentication failed. Check your Arize Phoenix API key and permissions.

What it means

Error "Authentication failed. Check your Arize Phoenix API key and permissions." thrown in BerriAI/litellm.

Source

Thrown at litellm/integrations/arize/arize_phoenix_client.py:88

            # Use the underlying httpx client directly to avoid query param extraction
            response = self.http_handler.get(url, headers=self.headers)
            response.raise_for_status()

            data: Final = response.json()
            return data.get("data")

        except Exception as e:
            # Check if it's an HTTP error
            response = getattr(e, "response", None)
            if response is not None and hasattr(response, "status_code"):
                if response.status_code == 404:
                    return None
                elif response.status_code == 403:
                    raise Exception(
                        f"Access denied to prompt version '{prompt_version_id}'. Check your Arize Phoenix permissions."
                    )
                elif response.status_code == 401:
                    raise Exception("Authentication failed. Check your Arize Phoenix API key and permissions.")
                else:
                    raise Exception(f"Failed to fetch prompt version '{prompt_version_id}': {e}")
            else:
                raise Exception(f"Error fetching prompt version '{prompt_version_id}': {e}")

    def test_connection(self) -> bool:
        """
        Test the connection to the Arize Phoenix API.

        Returns:
            True if connection is successful, False otherwise
        """
        try:
            # Try to access the prompt_versions endpoint to test connection
            url: Final = f"{self.api_base}/prompt_versions"
            response: Final = self.http_handler.client.get(url, headers=self.headers)
            response.raise_for_status()
            return True

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Check the Arize Phoenix API key and its permissions.

When it happens

Trigger: Thrown at litellm/integrations/arize/arize_phoenix_client.py:88 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/afba4f85e3c4e1c9. Report an issue: GitHub.