[Asterisk-Users] "404 User Not Found" when calling between two X-Lites

[Abraham WEI]

The configuration for X-Lite in sip.conf:
[177209]
;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

[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

The 2 X-Lites  registered well with username 177209 and 177210
respectively. When I made a call between them, I got "404
User Not Found" message from asterisk.
     Any idea?

X-Lites both run on Microsoft Windows XP Professional.
asterisk 1.07 runs on Red Hat Linux 7.3.

Abe