HDX 8000 disconnects from Lync conference after a minute

[Anonymous]

Dear all,

We installed HDX 8000 in the office meeting room and integrated it with already implemented Lync 2010 infrastructure. HDX has Mplus and RTV licenses enabled. The firmware is 3.0.5. When I'm creating a video conference between 2 Lync clients and HDX and fist inviting HDX then the Lync client the conference is working fine. If I'm inviting Lync client fist Polycom disconnects after one minute. What can be the reason?

I can't find any clue in debug logs neither in HDX

2012-10-04 11:56:55 DEBUG avc: pc[0]: uimsg: [A6d97: 20000 hangup 40]
2012-10-04 11:56:55 DEBUG avc: pc[0]: COMM: Hanging up connection SIPConn[0] cause code 16
2012-10-04 11:56:55 DEBUG avc: pc[0]: SIPConn[0]: hangup, cause code 16

nor in Lync

TL_INFO(TF_PROTOCOL) [10]0E68.1570::10/04/2012-11:56:53.570.00011387 (SIPStack,SIPAdminLog::TraceProtocolRecord:SIPAdminLog.cpp(125))$$begin_record

Trace-Correlation-Id

: 315853280

Instance-Id

: 004E7836

Direction

: incoming

Peer

: 10.15.15.15:40947

Message-Type

: request

Start-Line

: BYE sip:test@xxxx.com;gruu;opaque=app:conf:focus:id:6DVZ9CVC SIP/2.0

From

: polycom <sip:polycom@xxxx.com>;tag=plcm_1878015278-3295;epid=8211290DF6C7CG

To

: <sip:test@xxx.com;gruu;opaque=app:conf:focus:id:6DVZ9CVC>;tag=B97B0080

CSeq

: 3 BYE

Call-ID

: 1878014673-3295

Via

: SIP/2.0/TLS 10.15.15.15:5061;branch=z9hG4bK1937899183-3295

Route

: <sip:hq-lync.xxxx.local:5061;transport=tls;opaque=state:T:F:Ci.R522700;lr;ms-route-sig=gbplCxQGa8sr6QywEHp348cYEGEHuDbmfX1IIH-wGejzC4lsdMuz9u1QAA>

Max-Forwards

: 70

Allow

: INVITE,BYE,CANCEL,ACK,INFO,PRACK,COMET,OPTIONS,SUBSCRIBE,NOTIFY,MESSAGE,REFER,REGISTER,UPDATE

Supported

: ms-dialog-route-set-update,ms-forking,replaces

User-Agent

: Polycom HDX 8000 HD (Release - 3.0.5_ne-22695)

Thanks in advance