There is a bug asociated with this problem CSCse39727
The error message "C5510-1-NO_RING_DESCRIPTORS" may be seen in certain network conditions when analog ports are connected to the PSTN and "supervisory answer" tones are enabled on these ports. The DSP associated with this message will restart affecting all ports associated with it.
Try this workaround
Under the analog voice-port, disable "supervisory answer dualtone xxx".
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...