How to setup iax from asterisk

Hi all,

I need to setup iax from asterisk, for example i have Pbx Asterisk in serverA with ip address : 192.168.1.63 and Pbx Asterisk in serverB with ip address : 192.168.1.221, How to i connecting two asterisk with iax?
i have iax.conf on server A :
[general]
register => syabil:syabil123@192.168.1.221
[serverB]
type=friend
user=syabil
secret=syabil123
host=192.168.1.221
trunk=yes
context=trial

iax.conf on server B:
[general]
register => tsabita:tsabita123@192.168.1.63
[serverA]
type=friend
user=tsabita
secret=tsabita123
host=192.168.1.63
trunk=yes
context=trial

extension.conf on server A:
[trial]
exten => _8XXX,1,Dial(IAX2/serverB/${EXTEN:1},30,r)

extension.conf on server B:
[trial]
exten => _7XXX,1,Dial(IAX2/serverA/${EXTEN:1},30,r)

extension sip from server A is 7000 and extension sip from server B is 8000, but when i dial from ext 7000 to 8000, there is no ring , here log from CLI Asterisk :
– Called IAX2/serverB/000
[Apr 15 11:27:16] WARNING[1197]: chan_iax2.c:10724 socket_process: Call rejected by 192.168.1.221: No such context/extension
– Hungup ‘IAX2/serverB-16698’
== Everyone is busy/congested at this time (1:0/0/1)
– Executing [8000@trial:2] Congestion(“SIP/7000-00000006”, “”) in new stack
== Spawn extension (trial, 8000, 2) exited non-zero on ‘SIP/7000-00000006’

What’s wrong in my config ? please help me. Thanks in advanced

You have no three digit extensions in extensions.conf. More generally, you have no locally terminating extensions.

Sorry David , i dont understand what do you mind, could you to explain more about that ? sorry i am newbie about that.,