@Said to be clear - this communication was scoped only to customers who are already using workspace IP ACLs already. That said, it's hard to know exactly why your scenario is failing - if you have a support subscription, you can follow the steps here to submit a support ticket. That would probably be the easiest way to diagnose the issue: https://docs.databricks.com/en/resources/support.html. You can also submit a support case by emailing help@databricks.com.