I don't understand why i keep getting this error:

Failed to retrieve the documents by query. Object { name: "MissingAppCredentials", description: "Missing credentials: `Kinvey.appKey…", debug: "Did you forget to call `Kinvey.init…" }

here is my code:

promise = Kinvey.init({
      appKey  : 'kid_WyOe8-s3pe',
      appSecret : 'xxx',
      sync  : { enable: true, online: navigator.onLine }
      }).then(function() {
        Kinvey.User.login('user01', '123');
      });