This problem could be a result of the installation of the patch MS06-019 . MS06-019 has been known to cause some issues with Unity
To resolve this issue, upgrade the permissions wizard to the latest version by visiting: Cisco Unity Tools.
Alternatively, you can also overcome this problem by removing the MS06-019 patch from the Cisco Unity partner Exchange server. .
The MS06-019 patch addresses Send As permissions on Exchange servers. Voicemail messages from outside or unidentified callers are now sent successfully by Cisco Unity and received by subscribers.
To obtain all undelivered messages received during a failure period, move all messages from the \CommServer\UnityMTA\Failed folder to the \CommServer\UnityMTA folder and restart the AvUMRSyncSvr service.
The BU does not test every known article patch but tests full service packs and as that is done the following document will be updated: