When you have a video call in Microsoft Skype for Business 2016, the video freezes with some conference room devices.
Recently the Skype for Business client has made a change to rely on the estimated send time to throttle picture-loss-indication Real-time Transport Control Protocol (RTCP) feedback. In the situation of bitstream corruption or network loss, video freezes until the next keyframe. Therefore, the Skype for Business client is expected to recover from network glitches automatically. However, some room device firmware does not provide valid Network Time Protocol (NTP)/Real-time Transport Protocol (RTP) timestamp pair in RTCP messages. This causes the Skype for Business client not to recover from video freeze.
Install the latest firmware version of your conference room device to make sure that it conforms with the NTP/RTP timestamp pairing. If the compatible firmware isn't available, install the October 10, 2017, security update for Skype for Business 2016 (KB4011159).