Cisco 7906G will not register with Asterisk

Hi There

I’m hoping someone might be able to shed some light on the following issue I’m having.

I’m trying to get a Cisco 7906G to register with Asterisk. I’m sure that I’ve configured the phone correctly and the auth user and password values are definately correct, but Asterisk constantly returns a SIP/2.0 401 Unauthorized error. I’ve followed suggestions on forums to set NAT=never and qualify=no for the extension; this worked one time, but now doesn’t seem to make any difference.

I’d appreciate any help or advice anyone can offer.