This issue occurs when a server-side administrator configures limited media port range for Microsoft Skype for Business or Microsoft Lync 2013 clients by using Windows PowerShell. However, the clients use a random port that is out of the range the administrator configured.
Resolution
To resolve this issue, install the June 9, 2015 update (KB3054791) for Lync 2013 (Skype for Business).Note Lync 2013 was upgraded to Skype for Business in April 2015.
