asterisk users - Apr 2005 - "404 User Not Found" when calling between two SIP UA's

The configuration for kphone in sip.conf:
[177204]
;Turn off silence suppression in X-Lite ("Transmit Silence"=YES)!
;Note that Xlite sends NAT keep-alive packets, so qualify=yes is not needed
type=friend
;regexten=1234                 ; When they register, create extension 1234
;username=xlite1
;callerid="Jane Smith" <5678>
host=dynamic
;nat=yes                       ; X-Lite is behind a NAT router
;canreinvite=no                ; Typically set to NO if behind NAT
disallow=all
;allow=gsm                     ; GSM consumes far less bandwidth than ulaw
allow=ulaw
;allow=alaw

The configuration for X-Lite in sip.conf:
[177210]
;Turn off silence suppression in X-Lite ("Transmit Silence"=YES)!
;Note that Xlite sends NAT keep-alive packets, so qualify=yes is not needed
type=friend
;regexten=1234                 ; When they register, create extension 1234
;username=xlite1
;callerid="Jane Smith" <5678>
host=dynamic
;nat=yes                       ; X-Lite is behind a NAT router
;canreinvite=no                ; Typically set to NO if behind NAT
disallow=all
;allow=gsm                     ; GSM consumes far less bandwidth than ulaw
allow=ulaw
;allow=alaw

X-Lite and kphone registered well with username 177204 and 177210
respectively. When I made a call between X-Lite and kphone, I got "404
User Not Found" message from asterisk.
      Any idea?

X-Lite runs on Microsoft Windows XP Professional. 
kphone runs on Red Hat Linux 9.0. 
asterisk 1.07 runs on Red Hat Linux 7.3.

Abe

I'm at a loss as to why my * box dosnt want to play nicely with 
Broadvoice.  Here is what my log files are showing:

Jul 28 16:33:43 NOTICE[1187]: -- Registration for 
'2017540019@proxy.dca.broadvoice.com@proxy.dca.broadvoice.com' timed 
out, trying again
Jul 28 16:33:43 DEBUG[1187]: Scheduled a registration timeout # 108
Jul 28 16:33:43 DEBUG[1187]: Stopping retransmission on 
'4329b55603c0ceee281f175a7591ca07@127.0.0.1' of Request 119: Found
Jul 28 16:33:43 VERBOSE[1187]: -- Got SIP response 404 "Not Found"
back
from 147.135.0.128
Jul 28 16:33:43 VERBOSE[1187]: -- Got SIP response 404 "Not Found"
back
from 147.135.0.128

I setup my trunk using the AMP, and here is the info i input.

OUTGOING SETTINGS
PEER DETAILS:
authname=2017540019
canreinvite=no
context=from-pstn
dtmf=inband
dtmfmode=inband
fromdomain=proxy.dca.broadvoice.com
fromuser=2017540019
host=sip.broadvoice.com
insecure=very
nat=yes
secret=my-password
type=peer
user=phone
username=2017540019

USER Context: sip.broadvoice.com
User Details:
context=from-pstn
dtmf=inband
dtmfmode=inband
fromdomain=proxy.dca.broadvoice.com
host=proxy.dca.broadvoice.com
insecure=very
nat=yes
secret=my-password
type=user
user=2017540019
username=2017540019

Register String:
2017540019@proxy.dca.broadvoice.com:my-password:2017540019@proxy.dca.broadvoice.com


anybody have any ideas?

thanks!