[Asterisk-Users] Registration failed for SIP

[Damian Minkov]

I'm using asterisk with XLite everything  is working.
But in the asterisk console I always receive some notice of Registration 
failed .
What is the reason for this?
How Can be fixed?

message :
Jul  1 16:18:29 NOTICE[65541]: chan_sip.c:6731 handle_request: 
Registration from 'damian <sip:damian at 10.1.1.11>' failed for '10.1.1.11'

Asterisk and Sip phones are all in one network , no nat.

Here is the Config in sip.conf

[phone1010]
type=friend
host=10.1.1.11
auth=md5
nat=no
reinvite=no
canreinvite=no
qualify=1000
dtmf=inband
callerid="Damian Minkov" <1010>
username=damian