Hi @ioliu,

First test your api key to make sure it is working. Type or paste the following into your web browser address bar:

https://api.themoviedb.org/3/movie/550?api_key=YOUR_API_KEY

If you get back json for the movie Fight Club then your api key is valid. If your key is valid, then to get help you need to post the api URL you are trying to access that gives your the error message. Replace your private api key with a string like "API_KEY" or "xxxxxx". Note that if you post programming code instead of a URL, you may not get much help because not everyone that monitors this forum is a programmer and your are responsible for your own code.

This is what I get:

{"adult":false,"backdrop_path":"/hZkgoQYus5vegHoetLkCJzb17zJ.jpg","belongs_to_collection":null,"budget":63000000,"genres":[{"id":18,"name":"Drama"}],"homepage":"http://www.foxmovies.com/movies/fight-club","id":550,"imdb_id":"tt0137523","original_language":"en","original_title":"Fight Club","overview":"A ticking-time-bomb insomniac and a slippery soap salesman channel primal male aggression into a shocking new form of therapy. Their concept catches on, with underground \"fight clubs\" forming in every town, until an eccentric gets in the way and ignites an out-of-control spiral toward oblivion.","popularity":65.664,"poster_path":"/pB8BM7pdSp6B6Ih7QZ4DrQ3PmJK.jpg","production_companies":[{"id":508,"logo_path":"/7cxRWzi4LsVm4Utfpr1hfARNurT.png","name":"Regency Enterprises","origin_country":"US"},{"id":711,"logo_path":"/tEiIH5QesdheJmDAqQwvtN60727.png","name":"Fox 2000 Pictures","origin_country":"US"},{"id":20555,"logo_path":"/hD8yEGUBlHOcfHYbujp71vD8gZp.png","name":"Taurus Film","origin_country":"DE"},{"id":54051,"logo_path":null,"name":"Atman Entertainment","origin_country":""},{"id":54052,"logo_path":null,"name":"Knickerbocker Films","origin_country":"US"},{"id":4700,"logo_path":"/A32wmjrs9Psf4zw0uaixF0GXfxq.png","name":"The Linson Company","origin_country":"US"},{"id":25,"logo_path":"/qZCc1lty5FzX30aOCVRBLzaVmcp.png","name":"20th Century Fox","origin_country":"US"}],"production_countries":[{"iso_3166_1":"US","name":"United States of America"}],"release_date":"1999-10-15","revenue":100853753,"runtime":139,"spoken_languages":[{"english_name":"English","iso_639_1":"en","name":"English"}],"status":"Released","tagline":"Mischief. Mayhem. Soap.","title":"Fight Club","video":false,"vote_average":8.436,"vote_count":27090}

I'm not sure if you still want help, if so you need to read the rest of the instructions given previously and post the api URL you are having trouble with, otherwise no one can help you.