I have had this issue sometime when the agent suddenly cannot log on to the selected device although that it worked the day before. The solution was then to do a hard resett (pull the powercord) on the hard phone so it did a total reboot and reregistered to call manager. Then it worked again to log on to the device. Try this
i wana thank you all for your responses,they were really very helpful.The login problem has been sorted.i had to associate the device with icm in the Application User page of User Management in the CCM as suggested by Branmill in his response.
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.