Connection refused. Unable to fetch the server.

Connection refused. Unable to fetch the server.

Am trying to set up external MS SQL data source. Have created a user with DB admin permissions and have created a System ODBC connection to the SQL server from the machine hosting ADSelfService yet each time I try to connect either using the above user or the sa account, I get "Connection refused. Unable to fetch the server".  I can ping the DB server from the application server. I have tried connecting with both the SQL server name and IP address and with and without the instance. As I am not a DBA, I am probably missing something obvious. Please help as I would like to evaluate and hopefully purchase your product.

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