Whenever I make an extension (a new one), I get this message when it’s supposed to go to voicemail. “I’m Sorry, an Error Has Occured” then it disconnects the call. Basically, our company has 3 digit extensions like 275, 276, etc. We are changing our extensions and moving things around per department, I made the extension 2050, and enabled voicemail and when it goes to voicemail it just says “I’m Sorry, an error has occured.” All of them are SIP extensions. Any help would be appreciated.
I am also seeing the same problem, and I too have 3 digit extensions. I had suspected this had something to do with the end point manager as that was starting to play up. Though after having removed it, it made no difference.
I will watch this thread with much anticipation.
Can you confirm the following for me. Using the GUI, under Reports > Asterisk Info > Voicemail Users (on the right hand side) do you have a context defined for all voicemail enabled extensions?
It appears on mine that those that are not working do not have a context defined, but checking on the individual extensions, the vm context is set to ‘default’
If anyone can shed some light on this I would be grateful
I have just done a bit more digging and found that in voicemail.conf I had a couple of lines that were  seperating other extensions configs. After removing these my voicemail enabled extesions started functioning.
Give this a try it may help.