The Call Back feature failed to work then reset the CCMSysUser password with the CCMPWDChanger utility. And also perform the following steps.
1. Reset the CCMSysUser password
2. Restart the Cisco Extended Functions (CEF) service on all servers. On the CCMAdministrator page, choose Application > Cisco CallManager Serviceability > Tools > Control Center. Check if the CEF is live. If it is not, choose this service and start it. If it indicates that it is live, choose the service and restart it.
3. Restart these services:
a. Computer Telephony Integration (CTI) manager service
b. Cisco Tomcat service
c. IIS Admin service
4. Verify that the Directory Integration has completed.