Cannot delete Voicemail. Phones Freeze

We are having a lot of issues with voicemail on our system. We are running version 2.8.1.4.

We are having two main issues. The first is that trying to connect to the voicemail from the phones is not working. When you try and listen to the voicemails you just get a busy signal, and then the phone locks up. We are using Aastra 6757i phones. The second issue is that when you log in to messages and recordings through a web browser, you can successfully log in to an extension and see the voicemails, but you cannot delete them. You can listen to them, but when you check the box and hit delete nothing happens. I did find this in the asterisk log files.

[Jun 1 10:29:18] NOTICE[3252] chan_sip.c: Call from ‘16’ to extension ‘vmail’ rejected because extension not found in context ‘from-internal’.

Any ideas? Thanks

you may want to check the permissions on the voice files in linux.