Problem in originating

Hi all,

I am using single port and im executing two originate command simultaneously and in the respondent side i disable my auto answer mode.so at once one originate command is working.Only if i answered the first call and the second originate command is working.

my sip.conf

[brekeke]
username = 8888
secret = 1234
type = friend
host = 192.168.1.83
fromdomain = 192.168.1.83
;externip= 192.168.1.212
disallow=all
allow=ulaw
allow=alaw
allow=ilbc
allow=G711
dtmfmode=inband
insecure=very
;nat=yes
context=model

extension.conf
[auto]
exten => _X.,1,Playback(demo-congrats)

[redirect]
exten => _X.,1,AGI(cscript,${FILENAME})
exten => _X.,2,Dial(SIP/${EXTEN})

Regards,
Dinesh.K]