No Host found during call forward

Hi,
I have a remote Asterix server, on which i have two user accounts 2000,2001. Using my sip phone i cal login to
both the accounts. Now i have installed an asterix server on my linux machine and i have created one acocunt 3333.
Dailing to 3333 directly also works.
Now my aim is to register 2000 to the local asterix server and divert all calls from 2000 to 3333 so that when i call from 2001 to 2000 its gets me connected to 3333.
While trying to configure this i am getting No Host found :3333
Please find below my details to sip.conf and exten.conf

sip.conf

[general]
port=5060
bindaddr=0.0.0.0
register => 2000:password@sip.myexternaldomain.com/2000

[3333]
type=friend
username=somename
secret=YYYYY
host=dynamic
context=myphones

[2000]
type=friend
allow=all
context=from-client
host=sip.myexternaldomain.com
fromuser=2000
secret=password
dtfmode=rfc2833

extensions.conf

[myphones]
exten => 3333,1,Dial(SIP/somename)
exten => _X.,1,SetCallerID(2000)
exten =>_X.,2,Dial(SIP/${EXTEN}@sip.myexternaldomain.com)
exten =>_X.,2,Hangup

[from-client]
exten=>_X.,1,Dial(SIP/3333)

Please help me on this error.