Call forwarding on asterisk

I want call other sip call manager with my asterisk call manager
please help

What exactly are you trying to do, in terms of the calling and what problems are you having? Calling between two SIP proxies (ie - Asterisk and SER) is a fairly straightforward proposition, as you may simply dial a SIP URI from Asterisk as follows:

exten => s,1,Dial(SIP/

guyz! Really need all ur help! I built a Digital Operator that initiates a function whenever i press 1. the following is my extensions_custom.conf file:-

#include => macro-dialout-default
include => macro-dial-trunk
#include => outrt-002-BRANCH
exten => s,1,Playback(loligo/please-enter-the)
exten => s,2,Playback(extension)
exten => s,3,Wait(3)
exten => _0XXX,1,Answer
exten => _0XXX,2,Dial(IAX2/boxA-user:123123@${EXTEN:1},30,r)
exten => _0XXX,3,Dial(SIP/myserver:passwordA@SIPserverA/${EXTEN:1},30,r)
exten => _0XXX,4,Congestion
exten => h,1,Hangup()

i dunno this is the proper way or not but just now when i’m testing it the call suddenly can make it through to another server but after that it fails to initiate again. any ideas watz the problem??