[Asterisk-Users] Failed to authenticate on INVITE

[Esteban Barrientos Abarca]

Hi!
I have an asterisk server, it has been running for a few months and everything is great. Now i need it working with a sip provider but i'm having some problems.
When i try to make a phone call i get this message:

-- Executing Dial("SIP/esteban-aad5", "SIP/XXXXXXXXXX at provider||rtT") in new stack
    -- Called XXXXXXXXXX at provider
Sep 30 13:38:59 NOTICE[98311]: chan_sip.c:6557 handle_response: Failed to authenticate on INVITE to'"esteban"<sip:XXXXXXXXXX at sip.myprovider.com>;tag=as34b3dbce'

this is in my sip.conf file 

[provider]
type=peer                 ; we only want to call out, not be called
secret=mysecret
username=XXXXXXXXXX
host=sip.myprovider.com
nat=no
canreinvite=no
fromuser=XXXXXXXXXX
fromdomain=sip.myprovider.com
context=sip
insecure=very

[esteban]
type=friend
host=dynamic
username=esteban
secret=mysecret
dtmfmode=RFC2833
mailbox=303 
context=sip


esteban is the username of the phone i'm dialing from.
Am i missing any parameter???
Thanks.

Esteban