Really apologies guys. Check this one
I think I opened all possible debug levels this time. Please let me know
BTW…
What I’ve noticed as well is this:
Reason: Q.850;cause=31,SIP;text=“S.ims.otenet.gr.261.011.310.00045 CSCF released the session because of USER DEREGISTRATION”
And I am thinking IF the problem …could be also… that my accounts (one main number + 5 more msn numbers) are keeping registering at the same provider AND under the same SIP account-credentials during an active call… Then, maybe REGISTER and DEREGISTER cannot be handled correctly on multiple trunks that they are using the same SIP account… 
Any thoughts about this???