If I had to guess I would say from your description that it may be a problem with either the CSS or Partition assigned to the MWI ports. That is why you can dial the MWI On/Off from the phone but the MWI ports can't.
Calling Search Space
If partitions and calling search spaces are used, from the drop-down list box, choose a calling search space that includes the partitions of the DNs on all phones whose lamps you want to turn on (the partition that is defined for a phone DN must be in a calling search space that the MWI device uses).
If partitions are being used, choose the appropriate partition from the drop-down list box. If you do not want to restrict access to the message-waiting device directory number, choose for the partition.
I think that my configuration in callmanager is correct. i have two global partition : PN0 for phone (logout) and PN1 for profiles (when users logged). i have added PTTVM for voice mail and CSS_VM witch contain in order : PN1,PN0,PTTVM.
I have also added : pilot number, voial mail ports, MWI in the PTTVM partition with CSS_VM.
In the unity i have just added one subscriber account and i didn't change anythings in the message notification page !
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...