Polycom installed on Asterisk

Pls am having a little challenge,i added a polycom soundpoint P321 phone, the phone can receive calls from other phones but it cannot make calls, see below the sip.conf:
[400]
type=friend
context=esofties
dtmfmode=rfc2833
secret=mypassword
host=10.0.0.80(ip of the phone)
mailbox=10@phone
disallow=all
allow=ulaw
callerid=400
progressinband=no,

Any help pls