Video is not accepted on RealPresent Group 500

Hello,

I use the RealPresent Group 500 connect to Lync server 2013, when make call from PC side, the skype for business client show "Video is not accepted". I can only make audio call.

I also see that I don't have Skype for Business Interoperability License on the Group 500, do I need to purchase license for connect to Lync server to make video call?

Thank you so much.

System Software version Release - 5.0.0-211246