Would you please check this sample call log, and see which IP address the HTTP request was sent out, and if you can ping it.
Phone Number: 617-712-3999 x4599
Caller ID: 516-484-4400
Timestamp: 10/30/2019 - 04:39:43pm EDT
It should able to reach it, and send the http request, but it failed, we need to resolve it so we can move forward.
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