End Point sending Unregister Request

[PFCCWA]

Hello,

We use GAD 764 and CounterPath Bria as end point.
For some users they are receiving unregister request (captured in bria end point log below) but want to determine how this is caused.
This user is not able to make outbound call (telephony error) or out of service for inbound in GAD after this occurs.

[i]REGISTER sip:<sipserverIP>:5060 SIP/2.0
Via: SIP/2.0/UDP <briaclientIP>:2198;branch=z9hG4bK-d8754z-afcf9a3978b9f517-1---d8754z-;rport
Max-Forwards: 70
Contact: <sip:<agentloginid>@<briaclientIP>:2198;rinstance=843b6ec5e37621a3>;expires=0
To: ""<agentloginid>""<sip:<agentloginid>@<sipserverIP>:5060>
From: ""<agentloginid>""<sip:<agentloginid>@<sipserverIP>:5060>;tag=364782d2
Call-ID: ZDcyNGIyYmViYTg0MWRhNTBkYjdmZWZjYTljY2RmNjI.
CSeq: 10 REGISTER
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
Supported: replaces
User-Agent: Bria release 2.5.4.28 stamp 60196
Content-Length: 0[/i]

What can I use to determine root cause?
thanks.

[cavagnaro]

Maybe the OPTIONS message is being rejected somehow after a while and therefore the endpoint unregisters? You have to capture the whole call flow happening to that end point so you can see what errors it is getting and try to fix them.