Hi,  so I think what is happening as different types of tools get routed to lakebase via different paths and I believe you need to open up an additional private link. The docs here explain it pretty well. https://learn.microsoft.com/en-us/azure/databricks/oltp/projects/private-link

I suspect you already have port 443 opened, as this is needed for general Databricks features which is why the things that work do work. But you also need the Inbound Private Link for performance-intensive services on 5432. Here is the doc https://learn.microsoft.com/en-us/azure/databricks/security/network/front-end/service-direct-private... note this in public preview so you would need to make sure it's enabled. 

I hope this helps.

Thanks,

Emma