Hi @uakz
The tutorial in question shows a lot of complicated code, which I do no offer my services to login and debug.
Please debug your code line by line to ensure all variables and values are as expected.
Many plugins / theme code can modify and cause issues with the posts returned by a WP_Query, so perhaps it is possible that another source is causing no posts to be found.
Most likely, it is a logic error in the code you have written that is causing the WP_Query to find no posts.
Thanks
E