@jeffrose said:
Try It Out - Not working?
As I'm getting started on the API, the "Try it out" feature would be helpful but it's reporting CORS errors for me.

Access to XMLHttpRequest at 'https://z4vrpkijmodhwsxzc.stoplight-proxy.io/3/configuration?api_key={{key-redacted}}' from origin   'https://developers.themoviedb.org' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: Redirect is not allowed for a preflight request.  

The API itself IS working but it's good to have an idea of what to expect

There can be 3 different problems.

A - If you are in Russia, in the surrounding Moscow, there is a problem with access to the TMDb API servers.
Look at this thread:
https://www.themoviedb.org/talk/6036ee9d4fd141003eae8534

B - You may be using Try it out feature.

You are probably sending your API Request directly from the Developers page.
https://developers.themoviedb.org/3/getting-started/introduction
Developers.themoviedb.org is hosted by https://stoplight.io/
And yes, he's in trouble.
This is the error response I get on developers.themoviedb:

Response    503 Service Unavailable  

Error: Network Error  
Check the developer tools console, it might have more information on the error.  
If you are using an Ad blocker, it is possible your Ad blocker is blocking the request.  

But if I use the URL directly in the browser I get the correct answer.
Copy the URL of the API Request and paste it into a new tab or window.

Travis Bell, the Manager, said (2021-01-15):
https://www.themoviedb.org/talk/600184fc6aa8e0004077e364?page=1#6001bbacbe4b36003d514ac3

Hi @ user,
I believe Stoplight has temporarily blocked the Try it out feature for our account
because too many people were using it as the source for their apps,
and not using api.themoviedb.org for some reason.
No timeline on getting it restored, but that's the problem.
Switch to use our proper production address, api.themoviedb.org.

C - CORS issue

In case you have not researched here in the Forum, below the link of 3 posts with similar problem.
Maybe it helps:
https://www.themoviedb.org/talk/5f621eae93388b003864513c
https://www.themoviedb.org/talk/5eb07271a13533001b72740a
https://www.themoviedb.org/talk/5f55e3dd713ed40037f090d4
https://www.themoviedb.org/talk/5f55e3dd713ed40037f090d4

Got it - I was on the developer page for configuration (https://developers.themoviedb.org/3/configuration/get-api-configuration) and clicking the Try It Out tab and expecting that to work.

Using the URL directly did work, and gave me the answers I need.z