I have MBG in DMZ clustered with Micollab and MiVB, I'm unable to place calls to other MiCollab softphone extensions, MIVB reply SIP/2.0 503 Service Unavailable.
from MiCollab user can call desk phone, reference to attached pcap image, call to 599 is ringing, but call to 710 (Micollab Softphone) is not, what could be the issue?