Hi,

We are trying to connect to an On-prem SQL Server instances using JDBC (we really want to use a Federated connection, testing JDBC first).  We have successfully done this for one of the SQL Servers we have, but cannot get it to work for the other.  We get an general error of "Connection refused".

Both SQL Servers are 2016.  The only difference between the configuration is that the SQL Server failing to work has an SQL instance setup i.e. the server host is hostname\instancename rather than just the hostname.

We've tried every variation of string we can think of (double slash, forward slashes, ASCII char), they either fail validation or get to the same error.  Networking confirms the traffic is hitting the SQL Server through our firewalls.

Anyone out there who is connecting to a SQL Server instance via Databricks JDBC / Lakehouse Federation who has any ideas what this might be?! 

Thanks, Nick.