SIP expiry problem

Hi there
I have a problem in sip account registration
I have a sip account, i can connect to my sip provider by some softphones like “3CX Phone” with this an it works correctly. but I wana have this sip in my asterisk like a phone line so that i can do some thing with it!
i do this configuration in my sip.conf:
[general]
register => username:secret@provideripaddress
[mycontext]
type=peer
host=provideripaddress
fromuser=username
secret=secret
context=incoming
allow=all
qualify=yes
deny=0.0.0.0/0
permit=provideripaddress
insecure=invite

But at registration time I get this message
WARNING[29859]: chan_sip.c:20061 handle_response_register: Got 423 Interval too brief for service xxxxxx@xxxxx, minimum is 300 seconds
Could you please help me about configuring this 300 sec for minimum?!

Search sip.conf.sample for expiry.