Our Interface with Twilio Phone# Stopped working

Our Interface with Twilio Phone# Stopped working

We have had a Twilio # routing calls to our help desk (Zoho Support) for the last month or so.   In the last week, it stopped working.   The user gets a message "Aapplication Error)  The log in Twilio shows us an attempt to use the API would not connect.   This seemed like a very simple setup, but something has changed.  It looks like the change was on the ZOHO side...Any help would be much appreciated.