When a telephone conference via Twilio / Notify is set with a reverse proxy involved and a conference call is started, the message: "This number is not yet configured. You will now be disconnected." is displayed.
There are various reasons why this issue might occur when there is a reverse proxy before the instance, but the main reason is the failure of Twilio signature validation. For this validation to pass successfully, the request being originated from Twilio should be sent to Servicenow from the reverse proxy with all the headers and parameters intact. The request shouldn't be modified. The only acceptable modification is the protocol in the URL. If the protocol is modified, the x-forwared-proto header should be set before sending the request to ServiceNow.
Steps to Reproduce
Set up Notify integration with Twilio on ServiceNow.
For more information, see the product documentation topic Configure Notify with the Twilio service.
Initiate a Conference call.
The call is disconnected with message "This number is not yet configured. You will now be disconnected."
If your reverse proxy is modifying the protocol, set the x-forwarded-proto header with the value that Twilio used to send the original request.
Related Problem: PRB1287875