BerriAI/litellm · error · HTTPException

Invalid or expired credential

Error message

Invalid or expired credential

What it means

HTTP 401 from MCP auth: the bridge envelope's signature/expiry check failed, or the referenced key is missing, blocked, or expired. It deliberately hides which check failed so an attacker cannot probe the envelope format.

Source

Thrown at litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py:800

        if not master_key:
            raise HTTPException(status_code=500, detail="Server misconfigured: master_key is not set")

        await MCPRequestHandler._run_pre_db_read_auth_checks(request=request, route=route)

        keys: Final = envelope_keys_from_master_key(master_key)
        result: Final = resolve_bridge_envelope(authorization_value, keys, datetime.now(timezone.utc), server.server_id)
        match result:
            case BridgeEnvelopeAdmitted():
                header_key: Final = server.alias or server.server_name
                if header_key is None:
                    raise HTTPException(status_code=500, detail="Server misconfigured: MCP server has no routable name")
                admitted: Final = await MCPRequestHandler._reload_admitted_principal(result.identity)
                await MCPRequestHandler._enforce_admitted_live_policy(admitted=admitted, request=request, route=route)
                injected: Final = {header_key: {"Authorization": result.upstream_authorization.get_secret_value()}}
                new_headers: Final = {**(mcp_server_auth_headers or {}), **injected}
                return admitted, new_headers
            case BridgeEnvelopeInvalid() | NotBridgeEnvelope():
                raise HTTPException(status_code=401, detail="Invalid or expired credential")
            case _:
                assert_never(result)

    @staticmethod
    async def _admit_gateway_session(
        authorization_value: str,
        request: Request,
        route: str,
        mcp_servers: list[str] | None,
    ) -> UserAPIKeyAuth:
        """Open a gateway DCR session bearer and admit the live litellm user it references.

        Identity-only sibling of :meth:`_admit_dcr_bridge_delegate`: the session token seals no
        upstream credential (those are vaulted per user, resolved at egress), so authorization is
        resolved fresh via :meth:`_reload_admitted_user` + the centralized policy gate rather than a
        mint-time snapshot. Pre-DB gates (size, IP, route allowlist) run first, mirroring the standard
        pipeline. Fails closed with the requested scope's ``invalid_token`` challenge on an expired,
        tampered, foreign, or refresh token, or a missing/deactivated/policy-rejected user."""

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Re-authenticate: the credential (token/cookie) is invalid or expired.
2. Check the Authorization header value.

Example fix

Obtain a fresh token and retry the request.

When it happens

Trigger: Thrown at litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py:800 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/00e9b55328bc1774. Report an issue: GitHub.