Hi Michael;

  Here is what I did for my SS2016 Express ...

1) Make sure that TCP/IP protocol support is turned on in SS. To do that, open the Computer Management console and navigate to the SS area. Once there, locate the Protocols for SS section and after highlighting, ensure that TCP/IP is installed and its enabled (not usually for SS Express), as follows:

2) The next item in the SS console, is to make sure that all aspects are turned on and that SS-X is listening on port 1433. Use the RHMB on the TCPI/IP protocol and then select properties. Then make sure that all TCIP protocols are listening on port 1433 by selecting the IP  Address tab page, scrolling to the end and making sure that for IPALL you set the value 1433., as follows:

3) now make sure that you can connect to SS-X in your PB IDE. Create a SS SNC native connection DB profile in your PB IDE. Make sure that you set the Server to /SQLEXPRESS, also - make sure that you set your Provider to SS2012 or higher if your using a recent SS version, as follows:

4) If you can connect to SS-X now from the PB IDE - then you are ready to do the same from your PowerServer. In AEM, create a new DataSource. Set the DS type to MS SQL Server Native Driver. Then set your Server property to \SQLEXPRESS and set the Port to 1433. Now supply your database name and user credentials & press the Test Data Source button. You should receive a succeeded message by AEM, as follows:

HTH

Regards ... Chris