OK ... by setting it to sip_add_contact_id = false solved this issue..
Can you kindly assist in how can we restrict WCS to use a fixed SIP port, currently it is using dynamic SIP ports from 30001 to onwards and on every restart it changes it... we have tried to apply the following setting but it failed.
With the settings recommended in this post, two ports will be used for SIP signaling alternately: 30000 and 30001. The last port in range must be even, and it is never used. So two ports is the minimum you can configure.