If you have detailed diagnostics from the Jabber Mac client, this would provide some more context to why it's displaying those errors. (Help > Detailed Logging enabled) (Help > Report a problem)
Another thing to check for would be DNS resolution of the configured servers when the Mac is VPN'd in. If Jabber cannot resolve the DNS name, it will not know where to connect to.
If the diagnostics are pointing towards a connectivity problem, but the firewall says it's wide open, then taking a packet capture on the Mac where Jabber is trying to register may illustrate what's going on at the network layer.
SIP traces provide key information in troubleshooting SIP Trunks, SIP
endpoints and other SIP related issues. Even though these traces are in
clear text, these texts can be gibberish unless you understand fully
what they mean. This document attempts to br...
Please find the attached HTML document, download and open it on your PC.
This provides an easy to use form where you simply answer a few
questions and it will render the proper jabber-config.xml file for you
to copy/paste. There is built in logic to verif...
[toc:faq]CUCM Database Replication is an area in which Cisco customers
and partners have asked for more in-depth training in being able to
properly assess a replication problem and potentially resolve an issue
without involving TAC. This document discusse...