Here are some stuff regarding the UCCX .
First of all , please check that under the menu Subsystems>Cisco Media , you have well CTI port defined. It is depending on your license.
For reminder , the JTAPI User is the user which will control the CTI Route Point and the CTI Ports ( Everything must be populated via the appadmin).
The RmCM user is the user which must control the agent extension and the supervisors. Don’t forget also to define under your agent/supervisor agent the primary line and the IPCC extension.
Define then the Telephony Call Control Group that you will use to define the amount of CTI ports that you will use for your script/applications. Don’t forget to click on the Show More button in order to configure correctly your ports
In your application script , the Maximum Number of Sessions has to match the CTI port that you have defined in your call control group. If it is not the case, then you can encounter the conditions where you will hit the default script message so the message “Sorry we are experiencing ……”.