For QxC cloud-connected gateways, there are no inbound ports which need to be open, as all communication is initiated from the private side by the gateway.
In the off chance your firewall or content filter blocks outbound ports, you will need to open UDP port 51820 for cloud management, or all outbound UDP ports to stream video outside the local network.
(( For On Premise systems please refer to the following KB: https://www.qumulex.com/kb/on-prem-port-forwarding ))