Hi @Lawrence Chen​ if you are an account admin and if you enabled the "Admin Protection" feature means you will have this limitation. To overcome this you can create a non-admin user with "no isolation shared cluster" or you can create other cluster mode with admin access.

Take a look at this document to know more about the "Admin Protection" feature and its benefits and Limitations

https://docs.databricks.com/administration-guide/account-settings/no-isolation-shared.html