# Py4j Security Error

* **Error Message**: `py4j.security.Py4JSecurityException: Constructor <> is not whitelisted`
* **Explanation**: This error indicates you are being blocked by Py4j security rather than the Immuta Security Manager. [Py4j security](https://documentation.immuta.com/2024.2/data-and-integrations/how-to-guides/configuration/simplified#2-configure-cluster-policies) is strict and generally ends up blocking many ML libraries.
* **Solution**: Turn off Py4j security on the offending cluster by setting `IMMUTA_SPARK_DATABRICKS_PY4J_STRICT_ENABLED=false` in the environment variables section. Additionally, because there are limitations to the security mechanisms Immuta employs on-cluster when Py4j security is disabled, ensure that all users on the cluster have the same level of access to data, as users could theoretically see (policy-enforced) data that other users have queried.