Hi Phong Vu,
While calling this API, Why My response is null. can you please help?
Attaching the Screenshot also.
It's because you don't have any created subscription. If you think you have one and it is not listed here, it is probably created from a different 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:
6 People are following this question.