Because, according to the data on this site, they have not yet aired. If they have aired you have to edit it on MovieDB, that's where this site gets the data from.
According to Moviedb and Trakt, this program will premiere in June. If this is not correct, you can change the ID in Moviedb, read more about this here: https://www.mijnserie.nl/nieuws/algemeen/10765-nieuwe-series-toereken-via-tmdb-of-trakt-wijzigen-enof -adjust-how-do-you-do/