asterisk users - Aug 2005 - Hang up as soon as other party picks up call

Hello,

I have an Asterisk box with a TE410P connected to a PRI line and agents with
X-Lite installed on the same LAN as the Asterisk server. Sometimes, when I
make outbound calls it hangs up as soon as other party tries to picks up the
call. Does someone ever experienced this situation?  On X-Lite, only
G711-ulaw is enabled and here is what i put in sip.conf:

[4001]
type=friend
username=4001
secret=4001
host=dynamic
context=callout
disallow=all
allow=ulaw

And below is what i get from Asterisk debug.

Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:5320 check_user_full: Setting NAT
on RTP to 0
Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:825 __sip_ack: Stopping
retransmission on '674C5258-069C-4AF8-8B58-317838C513D3@192.168.1.40' of
Response 37605: Found
Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:5320 check_user_full: Setting NAT
on RTP to 0
Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:7140 handle_request: Check for res
for 4001
Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:1652 update_user_counter: Call
from user '4001' is 1 out of 0
Aug  2 11:04:17 DEBUG[180235]: chan_sip.c:4538 build_route: build_route:
Contact hop: <sip:4001@192.168.1.40:5060>
    -- Executing Dial("SIP/4001-40ee", "Zap/g1/6152437") in
new stack
    -- Called g1/6152437
Aug  2 11:04:17 DEBUG[557083]: rtp.c:1166 ast_rtp_write: Ooh, format changed
from UNKN to ULAW
Aug  2 11:04:22 DEBUG[262160]: chan_zap.c:1186 zt_enable_ec: Enabled echo
cancellation on channel 1
    -- Zap/1-1 is ringing
Aug  2 11:04:22 DEBUG[557083]: channel.c:1436 ast_indicate: Driver for
channel 'SIP/4001-40ee' does not support indication 3, emulating it
Aug  2 11:04:22 DEBUG[557083]: channel.c:1551 ast_prod: Prodding channel
'SIP/4001-40ee'
Aug  2 11:04:22 DEBUG[557083]: channel.c:1128 ast_settimeout: Scheduling
timer at 160 sample intervals
Aug  2 11:04:22 DEBUG[557083]: channel.c:1128 ast_settimeout: Scheduling
timer at 0 sample intervals
    -- Channel 0/1, span 1 got hangup
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:2427 zt_setoption: Set option
AUDIO MODE, value: ON(1) on Zap/1-1
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:1940 zt_hangup: Hangup: channel: 1
index = 0, normal = 28, callwait = -1, thirdcall = -1
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:2076 zt_hangup: Not yet hungup...
Calling hangup once with icause, and clearing call
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:1218 zt_disable_ec: disabled echo
cancellation on channel 1
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:2339 zt_setoption: Set option TDD
MODE, value: OFF(0) on Zap/1-1
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:1161 update_conf: Updated
conferencing on 1, with 0 conference users
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:2421 zt_setoption: Set option
AUDIO MODE, value: OFF(0) on Zap/1-1
Aug  2 11:04:28 DEBUG[557083]: chan_zap.c:1218 zt_disable_ec: disabled echo
cancellation on channel 1
    -- Hungup 'Zap/1-1'
  == No one is available to answer at this time
Aug  2 11:04:28 DEBUG[557083]: app_dial.c:1025 dial_exec: Exiting with
DIALSTATUS=NOANSWER.
    -- Registered '2002' (AUTHENTICATED) at 192.168.1.41:4569
    -- Registered '3002' (AUTHENTICATED) at 192.168.1.54:4569
Aug  2 11:04:38 WARNING[557083]: pbx.c:1933 ast_pbx_run: Timeout, but no
rule 't' in context 'callout'
    -- Executing SetCDRUserField("SIP/4001-40ee",
"STATUS=NOANSWER") in new
stack
Aug  2 11:04:38 DEBUG[557083]: cdr_addon_mysql.c:178 mysql_log: cdr_mysql:
inserting a CDR record.
Aug  2 11:04:38 DEBUG[557083]: cdr_addon_mysql.c:197 mysql_log: cdr_mysql:
SQL command as follows:  INSERT INTO cdr
(calldate,clid,src,dst,dcontext,channel,dstchannel,lastapp,lastdata,duration
,billsec,disposition,amaflags,accountcode,userfield) VALUES ('2005-08-02
11:04:17','\"4001\"
<4001>','4001','6152437','callout',
'SIP/4001-40ee','Zap/1-1','SetCDRUserField','STATUS=NOANSWER',21,0,'NO
ANSWER',3,'','STATUS=NOANSWER')

Thanks for any tips

Lamine