Why does filtering return null after entering a category?

For example, I choose with_genres string "28", first_air_date_year "2000"

Full url:

https://api.themoviedb.org/3/discover/tv?first_air_date_year=2000&include_adult=false&include_null_first_air_dates=false&language=en-US&page=1&sort_by=popularity.desc&with_genres=28

I receive:

{
  "page": 1,
  "results": [],
  "total_pages": 1,
  "total_results": 0
}