Voicemail hangs up before taking message (external callers)

It’s been quite some time since I’ve used Asterisk. However, I have a client that is an active law firm that is using it.

Currently, if you call in and access the automated attendant and select an option (that forwards to the respective extension), you are greeted with the message “Extension…” and it hangs up part way through the outgoing message. The user has recorded and outgoing greeting which plays normally when an internal extension calls them.

So, the long and short is, external callers get a hangup after playing the word “extension” and internal users function flawlessly. This is not the case for all users on the system. Some work without problem.

Users can access the voicemail system and record a new outgoing greeting which I’ve had them do. Any ideas?