After the Cisco CallManager is upgraded to version 4.2(3), the Cisco Unity Express reports that it is unable to determine the Cisco CallManager version when it verifies the Web and Java Telephony API (JTAPI) username and password information.
Cisco CallManager disables non-secure access to the http://x.x.x.x/CCMPluginsServer/CiscoJTAPIClient.exe URL in versions 4.2(3) and later. The Cisco Unity Express relies on this URL in order to determine the Cisco CallManager version. As a result, it fails to detect the correct Cisco CallManager version. But, the default Cisco Unity Express JTAPI jar (skate, 4.1) registers successfully to a Cisco CallManager 4.2(3), and it is not possible to make calls.
This issue is found in Cisco CallManager version 4.2(3) with these supported versions of Cisco Unity Express:
All functionality remains. The Computer Telephony Integration (CTI) ports and route points register with Cisco CallManager. The voicemail (VM) and auto attendant (AA) route points are functional and able to be dialed.
This issue is documented in Cisco bug ID CSCsg11684
The workaround for this problem is to disable Secure HTTP (HTTPS) for the URL. Complete these steps on the Cisco CallManager: