@studio.myritebook said:
API Key
API key is not working...

Take a Test

Click to go to your Profile > API: https://www.themoviedb.org/settings/api
At the bottom of the page, below, you'll find the Example API Request.
https://api.themoviedb.org/3/movie/550?api_key=THE_KEY
Use this example to do a search using a new tab in your browser.
You will receive the basic data of the Movie Fight Club (1999)
https://www.themoviedb.org/movie/550-fight-club
If it works, your Key is OK.

When there is a problem, the TMDb Server sends a message.
Can you tell which message the server sent?
Here is a list of possible messages:
https://www.themoviedb.org/documentation/api/status-codes

If it does not work, let us know right here.

I am trying to give access this API key in wordpress, says key is invalid

@studio.myritebook said:
I am trying to give access this API key in wordpress, says key is invalid

The only way I know to check if your API Key is valid is by doing the test I indicated above.
Did you take the test?
What was the result ?

OK. Got it