Call forwarding issue Zendesk

I recently replaced my phone/modem with a new Xfinity replacement this week. I am having issues receiving phone calls to my Xfinity landline from my work laptop program Zendesk. I contacted Zendesk directly and they said there is no issue on their end that is must be Xfinity. I have never had a problem all this time.I have always been been able to receive calls to my landline. It just happened once I replaced the modem. Zendesk told me that they can see the system attempts to forward the call to my landline but there is no response from the Xfinity network. Then the call terminates with the status: "Call ended with receiving provider" I am wondering if something can be done to fix this on the Xfinity side? Thanks!