Usually the m100 would register to a Gatekeeper and I am not to familiar if it can just dial an IP Address without being registered to such.
Another issue could be the PC's Firewall or a Firewall in your Network.
I would recommend your IT Team to run a wireshark trace to see if there is any outward communication from the Application to your Network.
The Ports that need to be opened on a Firewall have been discussed plenty of times and a forum search should highlight these for you.
Polycom Global Services
---------------- The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.
Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels. Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's