Not receiving calls on registered ITSP

Hello everyone
I’ve registered with my ITSP (sip show registry says so)
And specified a section for it:
register => AAAAAA:BBBBBB@DOMAIN/AAAAAA
[AAAAAA]
host=DOMAIN
username=AAAAAA
secret=BBBBBB
type=friend
allow=all
context=entrantes
fromdomain=DOMAIN
fromuser=AAAAAA

And in my extensions.conf I have:
[entrantes]
exten => s,1,Answer()
exten => s,2,Set(TIMEOUT(digit)=7)
exten => s,3,Set(TIMEOUT(response)=20)
exten => s,n,Background(demo-thanks)
(continues, but it’s quite long)

The thing is, I call to AAAAAA external number (wich is 00AAAAAA), and I’m not receiving any call, also, I’m not seeing any messagein * console.

Any tips/help would be greatly appreciated.
Best regards.
Tai.

[EDIT]
Provider is telling me that they receive “error 401: Unauthorized” on their side.

Any thoughts on this?
I’m having quite a bad time trying to figure out what’s wrong…
Thanks in advance.

Solved this - Now problem is I’m getting ‘busy’ tone. I have no messages in console (verbosity = 4).
Any thoughts on this ?

New update - Busy tones is because of 'No compatible codecs’
Best regards.
Tai.