With Monitor 5.6 installed on a machine, there may be an issue initiating Lync video conferencing. When the video conference call is initiated, the recipient may fail to receive notification of the call. Additionally, the sender's Lync window may freeze or continually load. If the sender attempts to exit the window, they will see a "waiting" cursor and eventually Lync will stop responding.
This issue can be avoided by uninstalling URL filtering on the sender's machine.
NOTE: The DyKnow executable installer will install URL Filtering regardless of whether or not the box (during install) is selected. The MSI component will allow you to deselect the URL Filtering component. To edit the MSI configuration, please read this guide.
The various properties may be found here. Specifically, please update the DONT_INSTALL_URL_FILTERING to 1. An install following this update should resolve the behavior.