Cisco UCCX IPPA clients slow or unable to log in or go ready - requesting or XML Parse Error

After some power outages in a data center hosting a Cisco UC enviroment, users using Cisco IP Phone Agent (IPPA) indicated they recieved only a "requesting" message in the phone display when attempting to log in or go ready.  If a user was able to get to a state where they were taking calls, they also reported seeing XML (4) Parse Error intermittantly between calls.

The users were equipped with IPPA and "one button login" only, but some remote testing using the CAD fat client indicated users could log in immediately if not already logged in.

The short story fix was restarting some services on CUCM and UCCX.  I would suggest using stop and start commands rather than restart commands and do them in this order.

Stop CTI Manager on CUCM Pub
Stop CTI Manager on CUCM Sub
Start CTI Manager on CUCM Pub
Start CTI Manager on CUCM Sub
Stop Cisco Tomcat on CUCM Pub (via CLI only with utils service stop Cisco Tomcat)
Stop Cisco Tomcat on CUCM Sub
Start Cisco Tomcat on CUCM Pub (via CLI only with utils service start Cisco Tomcat)
Start Cisco Tomcat on CUCM Sub
Stop IPPA service on UCCX
Start IPPA service on UCCX


Note: there were only two CUCM servers and one UCCX server deployed.

Note:  This process will be business impacting in this scenario.  CUCM CTI Manager is responsible for applications using JTAPI (and TAPI) so UCCX will out of order at this point.  The UCCX IPPA service handles requests for agents using IPPA so you'll likely be logging agents out at this point.