@qishuai said:

Why, when searching on the TMDB page:
https://www.themoviedb.org/search?query=%D8%A7%D9%84%D8%A2%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A
The content with id=259457 will be returned.

Query the same keywords and call the TMDB API:
https://api.themoviedb.org/3/search/multi?api_key={API_KEY}&query=%D8%A7%D9%84%D8%A2%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A&page=1
But it will not return the content of id=259457.

I tested it now and received the correct answer..

https://api.themoviedb.org/3/search/multi?api_key=THE_KEY&query=%D8%A7%D9%84%D8%A7%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A

I found a difference.
It must be a different character.
A2 and A7

%D8%A7%D9%84%D8%A2%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A
%D8%A7%D9%84%D8%A7%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A

%D8%A7%D9%84%D8%A2%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A
%D8%A7%D9%84%D8%A7%D9%86%D8%B3%D8%A9%20%D9%85%D8%A7%D9%85%D9%8A