Quality of Service (QoS) is a mechanism to prioritize Voice over IP traffic on your network. This is used to prevent other packages on the network from disrupting the phone traffic. When QoS is not used in the network, high intensive traffic such as video streaming and file downloads could cause performance issues and degraded call quality.
Your network administrator can set the QoS to prioritize the IP address of your Wildix Collaboration system. Each customer has a static IP address or IP addresses for the system that is exclusively assigned to your system. Some systems offer the option to set domains in the QoS settings, if this is possible you can set your YOURSUBDOMAIN.wildixin.com URL as the domain for the QoS settings.