The voicemail system is critically short of memory which has resulted in its instability since yesterday's power outage. Users will have noticed this in the form of intermittent access to the voicemail number (8570) and with the viewmail software. In addition, phones that were diverted to voicemail at times when the system has been down will have rung without being answered.
This problem is in the process of being addressed (additional memory is being installed) and things should normalise during the course of the morning.