ReasonCode 16: DuplicateRegistration. This means that Cisco Unified CallManager detected that the same device was registered on two nodes at the same time. When this happens, Cisco Unified CallManager sends a restart request to the phone to force the phone to register with only one Cisco Unified CallManager.
I believe this can happen if a phone loses contact with its Primary CUCM and moves to the Secondary CUCM and registers before the de-registration on the Primary has been fully completed. I'm pretty sure this is a fairly rare network related problem.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.