I guess, you have set the multiple login as "not allowed". If this is the case, then when the user logs on the first time, it will be successful. But the second time onwards, it fails until you logout. With this feature, Extension Mobility supports only one login at a time on a device. Try to disable this and it should work.
Check the same document for the following point(4th one) :
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...