So, as others have confirmed here, to recap, installing Ensemble 2018 on an instance of Windows that already has IIS installed - plus, you take the defaults when installing Ensemble .. should have installed the CSP gateway on IIS.

Is there an installation log file worth reviewing for any clues ? (I believe there is ensemble-install log in the installation root folder). 

Just a thought...

Are you using the IRIS ODBC Driver when connecting to IRIS from DBeaver (or C#)?

Hi.  Note (which should be obvious), the typo in that there are only two 't's in http, so:

http​​​://localhost:52773/terminal/