My client has several phones that display this error message while on hook. I have used the web interface to the phones in question and the Information, Directories, and Services URLs are all by IP address, not by by host name.
Phones function correctly, just have this error message on the idle display.
Maybe turn on 'span to pc port' and 'pc port vlan access' and run a wireshark trace on the pc port of the phone. You may see some XML commands being sent in to the phone from an application of some sort. If not, you should at least see what URL the phone is trying to reach which should give you a clue!
Alternately try browsing to the phone and check the console logs for any entries suggesting what it it trying to reach.
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.