Zoom Contact Center Audio

Hi, I have the same issue. Our IT team checked if anything was blocking the voice but found nothing. If you already found the solution please reply. 

this should help narrow down the ports:
Zoom network firewall or proxy server settings

I still think Zoom needs to segregate the IP list to smaller chunks based on geolocation. you can't expect an organization to open up to soo many external IPs/subnets.