We have identified an issue where SQL Express uses dynamic high port that is also used by Skype for Business MCU, Mediation or EDGE and breaks the Media connectivity. In this scenario the SQL Express takes for example TCP 49166 which may be used by Audio/Video & Application Conferencing Server including the Mediation Server and EDGE Server. This is highly exceptional that the Ports collide between SQL Express and Skype for Business Media Ports but I have seen it happen on customer deployments.
This is a screenshot of an SQL Express using TCP 49166 which is in the Port Range of Application Sharing Server (default configuration of Port Ranges for Application Sharing is 49152 – 65535)
Workaround is to configure SQL not to listen on the IP Address of the Server but only localhost (ex. 126.96.36.199) or change the dynamic port on the SQL Express Service, or set the configuration from Enabled = No & Active = No for the desired interface (ex for EDGE)
In the long run Microsoft should solve this during installation of Skype for Business: The SQL Express is deployed as part of the Skype for Business deployment wizard and should be configured appropriately during install.