I was working on an issue like the one you are experiencing. There are some things that you need to check in your CUE and CME to confirm that everything is configured fine.
1) Make sure that under CUE Admin page -> Users -> CUCME, you have the correct information:
Hostname: CUCME Ip address
Web username: the user listed in telephony service (Web admin system user xxxx password xxx)
2) You need to make sure that CUE is sync with CME
- You can go to CUE Admin page -> Administration -> Synchonize information and make sure that CUE is synchronized with CME.
3) Here is one of the most importants things, you need to make sure that you are able to logging into the CME GUI http://xxx.xxx.xxx.xxx/ccme.html, if you are not able to logging that could be your issue.
Note: The GUI Files are not on the router by default, so if you go to http://xxx.xxx.xxx.xxx/ccme.html and it is not displaying the CME admin page, it could be because the router does not have the GUI files, you can go to Cisco.com -> Download Software -> Cisco CallManager Express and download the correct .tar file for your CME version (show telephony Service).
I was able to fix my issue after installing the GUI files on the router. Before installing the GUI files, I went to
CUE Admin page -> Administration -> Synchonize information and it said that CUE was NOT sync with CME, after install the CME GUI Files, I went again to the path and the information was in sync.