There are two authentication tokens that can be found on this page: https://www.themoviedb.org/settings/api

To use the "Try It" test in the api docs you have to use the "API Read Access Token" and -not- the "API Key" found on the above page.

Or, you can log in to the api docs and the keys will be autofilled:

1. click on the "Log In" button in the upper right corner (this will set your api key and access token)
2. make sure the authentication header is set to "Access Token Auth" (the default)

Aha! My problem was API Read Access Token. now it response success.

i have another question, if i make java language program. which key is right to make connection? API Read Access Token or API Key?

The differences are in how they are used.

The "API Key" is always passed in the url, as "api_key=THE_KEY". For example: https://api.themoviedb.org/3/movie/550?api_key=THE_KEY

The "API Read Access Token" is always passed in the header, as "Authorization: Bearer THE_TOKEN".

Either one can be used on most call methods, the exception being that the API Read Access Token is required for v4 calls.

So the language doesn't matter, you just need to construct the correct queries using the above rules.

Thank you for letting me know this. You've been a great help.

P.S. for anyone else who finds this post, there's a page in the docs outlining this here.

Thanks!