...The template is configured to use an in-memory database by default. This ensures that all users will be able to run the solution without needing to set up additional infrastructure (e.g. SQL Server). Verify that the DefaultConnection connection string within appsettings.json points to a valid SQL Server instance. When you run the application the database will be automatically created (if necessary) and the latest migrations will be applied. This will contain all entities, enums, exceptions, interfaces, types and logic specific to the domain layer.