I am using ringcentral api for ringout in Dev sandbox. But unfortunately I am getting exception:
"message": "Forbidden", "errorCode": "InternationalProhibited"
If you are using Dev sandbox as you said in your question, that is free service for developers on Sandbox, and international calling is prohibited there.
check the link:
Your sandbox account doesn't support international calling. Maybe the production env have this feature.
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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