Problem
When you open Cisco Jabber Mobile and try to login you receive an error
"Cannot comunicate with the server. Diagnostic."

Source
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvz20720

Solution
You have to import you internal Root CA used by ExpressWayC to Cisco Unified Call Manager CUCM
1. Go to Cisco Unified OS Administration
2. Security
3. Certificate management
4. Check if under "tomcat-trust" and "callmanager-trust" is present the Internal Root CA
5. if not import it as PEM "internal-root-ca.cer"
6. Go to Cisco Unified Serviceability
7. Tools
8. Control Center – Feature Services
9. Restart "Cisco CallManager"
10. Restart "Cisco TFTP"
11. Connect in SSH to CUCM and do a "utils service restart Cisco Tomcat"

Check in you ExpressWayC web page
1. Status
2. Unified Communication status
3. View SSH Tunnel Status
4. Check if all tunnel are Active

Now you can try to login with Cisco Jabber Mobile again