Extensions register and are able to make calls, just not recieve

Hi all,

I have been frustrated with a recent problem and have decided to consult the experts.

I have a few Cisco 7940s and I am running into an issue with the extensions registering and able to make calls, but are unable to receive calls.

All calls to the extensions go straight to voicemail and the phone does not ring.

I have a sample CDR report from when I attempted to dial extension 2007 from 2006.

2014-01-14 20:32:31 CHAN_START 2006 - 7940 Watson Desk 2006 DEFAULT 2007 from-internal SIP/2006-0000005c
2014-01-14 20:32:31 CHAN_START 2007 - 7940 Watson Desk 2007 DEFAULT s from-internal SIP/2007-0000005d
2014-01-14 20:32:32 HANGUP 2007 - 7940 Watson Desk 2007 2007 DEFAULT 2007 from-internal AppDial SIP/2007-0000005d
2014-01-14 20:32:32 CHAN_END 2007 - 7940 Watson Desk 2007 2007 DEFAULT 2007 from-internal AppDial SIP/2007-0000005d
2014-01-14 20:32:32 ANSWER 2006 - 7940 Watson Desk 2006 2006 2007 DEFAULT s-NOANSWER macro-vm VoiceMail SIP/2006-0000005c
2014-01-14 20:32:38 HANGUP 2006 - 7940 Watson Desk 2006 2006 2007 DEFAULT h ext-local SIP/2006-0000005c
2014-01-14 20:32:38 CHAN_END 2006 - 7940 Watson Desk 2006 2006 2007 DEFAULT h ext-local SIP/2006-0000005c
2014-01-14 20:32:38 LINKEDID_END 2006 - 7940 Watson Desk 2006 2006 2007 DEFAULT h ext-local SIP/2006-0000005c

I am just wondering if this is a phone, routing, or extension issue and if you can point me towards finding a solution?

Thanks