Check this blog to see if this helps.
i created an API from ring central developer beta site but when i try to put in wordpress plugin the credentials it says error validating credentials. how can i solve that issue
After you created an app, the app is active in your sandbox account. You need to login with a user in your sandbox account and test the app before you can graduate it to the production. After that, you will need to use the app credentials for production and login with a user under your production account. Read these developer guide for details.
https://developers.ringcentral.com/guide/basics/create-app
Using the RingCentral Phone for Desktop, you can dial or receive test calls, send and receive test SMS or Fax messages in your sandbox environment.
Download RingCentral Phone for Desktop:
Tip: switch to the "sandbox mode" before logging in the app:
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