Hi S.T.,
This is the default message displayed after installing a site before you have configured it and added pages/page types, content, etc. This is noted at the end of the following page in that tutorial: https://docs.kentico.com/13tutorial/developer-tutorial/asp-net-core-development-tutorial/configuring-the-core-application
If you look in the project files for the live site, you will see this message in the Startup.cs file as the response when visiting the "/" route, so the fact you are seeing this indicates that your site is running correctly. You will address this further in the tutorial once you have content and pages created.