[Asterisk-Users] Setup problems

[pete]

I am totally new to this project, I have been trying to set it up now for
almost a whole day, and can not understand what is wrong. The following
error appears when my phone tries to register:

Oct  6 19:08:30 NOTICE[98310]: chan_sip.c:7519 handle_request: Registration
from '<sip:2201 at 192.168.0.5;user=phone>' failed for '192.168.0.253'

What exactly does this error mean, apart from that registration failed.
Anyone any ideas why it failed?
My phone is a IP2006 ( http://www.solwise.co.uk/voip-phones-ip2006.htm )
Have double checked and triple checked the password.
Thanks in advance

pete