Extensions using voipcheap or others

Hello,

I have added for 2 extensions to call each other and to use VoipCheap.com as for externel calls.
I’m geting error in asterisk log :
Here is the error:

-- Executing Dial("SIP/toli-8d0b", "SIP/nonumber-out") in new stack -- Called nonumber-out -- Got SIP response 400 "Bad request" back from 80.239.235.192 -- SIP/nonumber-out-a09c is circuit-busy == Everyone is busy/congested at this time (1:0/1/0)
My sip.conf is :

[code][general]
defaultexpirey=1800
dtmfmode=auto
qualify=yes
register => USERNAME:PASSWORD@sip.voipcheap.com
disallow=all
allow=all

[nonumber-out]
type=peer
host=sip.voipcheap.com
username=USERNAME
secret=PASSWORD
nat=yes

[toli]
username=toli
secret=toli
allow=all
context=nonumber
type=friend
host=dynamic
nat=yes
qualify=10000

[niki]
username=niki
secret=niki
allow=all
context=nonumber
type=friend
host=dynamic
nat=yes
qualify=10000[/code]

And my extensions.conf is:

[code]
[general]
static=yes
writeprotect=no
autofallthrough=no
clearglobalvars=no
priorityjumping=no

[nonumber]
exten => 101,1,Dial(SIP/toli)
exten => 102,1,Dial(SIP/niki)
exten => _9.,1,Dial(SIP/nonumber-out)[/code]

Thank you for your help!!

Regards