Extension just rings all of a sudden voicemail never picls up

[mcarpani]

Mitel 5000 unit that has been working well for a while all of a sudden one of the extensions just rings and never forwards to users vm. We have checked the forwarding paths, I have looked everywhere in the DB Programming by comparing the flags to a good ext and they are all the same with system forwarding set to yes.
I have also looked at the forwarding options and verified against a good path. I even deleted the ext and re created it by copying a known good ext. I have also re created the users mailbox and copied again from a working mbox.
I thought maybe the user entered a feature code on accident so I reset the handset to factory and re assigned to the ext.

It just will not forward to vmail, can someone help me out with anything I might have looked over?

[DND ON]

Is DEE programmed for this user or is the phone manually forwarded somewhere?

[mcarpani]

I do not beleiev DEE is programmed or the ext is manually forwarded but is there a place to check this in the db programming?

[mcarpani]

Internal calls do not go to voicemail but external calls do go to voicemail

[mcarpani]

Simple setting missed in the Forwarding path, IC Calls was set to No and should have been set to yes.
Thank you to all that replaied. Double and triple check settings, can be easily missed.