My inbound calls have stopped working (OpenVFX).
It's been happening for about a month now, but I've been very lazy and have just gotten around to looking at the issue.

One thing I've noticed is that I frequently get the message "[2014-07-02 23:52:04] NOTICE[2999]: chan_sip.c:15135 sip_reg_timeout: -- Registration for 'xxxxxxxx@pan.wxnz.net' timed out, trying again (Attempt #51)"
Out bound calls are perfectly fine BTW.
There haven't been any changes to the environment (other than a SonicWall firmware update I did a while ago).
I can ping pan.wxnz.net (182.154.16.150) fine.
Other information:
CLI> sip show channels
Peer User/ANR Call ID Format Hold Last Message Expiry Peer
182.154.16.150 xxxxxxxx 483333333333335 (nothing) No <guest>
CLI> sip show peers
Name/username Host Dyn Forcerport Comedia ACL Port Status Description
VFX/abcdefghijklmnopqr 182.154.16.150 Yes Yes 5060 OK (21 ms)
I'm on an Orcon connection (for what it's worth).
Any ideas anyone?
Cheers