Provide details as what you provide in the API call, what happens and what kind of error it returns. Just "Not working" does not help anyone to help.
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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