When deploying the CCU to workstations, the UI prompts for credentials. A user enters a password for thier target account and CCU validates the match in the ini file. At that point CCU caches the credentials. However, the CCU may not move on to processing and instead closes the UI followed by prompting for credentials again. No errors may be generated in the logs.
Check the logs for the following line:
QueryUserDialog( eventSignalCheck ) = 0 CacheCredSvc.cpp Line:1656
If present, this indicates that the 30 seconds time out has been reached triggering the executable to run again.
This is often the result of an environmental situation on the network/vpn reach to the target domain.
To prove this is the situation one possible test is to join a computer to the target network over the same vpn. This may indicate networking issues and to take appropriate action.