I have little experience with API.  I'm trying to get a Custom API working with Zoho creator.  I have created a Custom API and created an Endpoint URL, but i get a 9400 error code "The provided HTTP method is not valid for this custom API".  Based off the documentation I am sending the request as just the Endpoint URL with the Public Key appending on the end.

https://www.zohoapis.com/creator/custom/<admin-user>/<custom-api>?publickey=<public-key>