[asterisk-users] got 404 when route calls through Asterisk to another proxy

[Jason Ma]

Buddies,
Here is my test case
softphoneA-->proxyA--->Asterisk-->proxyB-->softphoneB
                                        |
                                  softphone C
softphoneC is registered with Asterisk.

I can place call from softphoneA to softphoneC,and also can make calls
from softphoneC to softphoneB.
But when I placed call from softphoneA to softphoneB,I got 404 not
found that sent from Asterisk.What wrong with my configuration?Need I
do someting to let Asterisk can receive inbound calls and chosse
proper routes and send it our?Please advise.Thanks a lot.