Take two identical databases on different SQL Server instances (or on prem vs Azure). Ensure they are identical by doing a schema compare. Take a data generation file that is configured and works for one database. Take that file and change the target to the new database. The pre-existing configuration does not get applied to the new database.

The workaround is to create a copy of the existing data generation file, open the new configuration .dgen file in a text editor and change the ConnectionString line in the xml to match the new database's properties. In order to get the new databases connection properties, you have to create a brand new database generation file for the new database and take it from that.

...Kris