It looks like PubNub-driven application is no longer working, as the subscription endpoint "https://platform.ringcentral.com/restapi/v1.0/subscription"; is throwing the 503 error with error code "CMN-201".
Is this particular endpoint going under maintenance (as the GET request indicates: "service is overloaded, please retry later"), or is it perhaps my mistake?
Let me know what your thoughts are.
Thanks!