On Thu, Mar 21, 2013 at 4:46 PM, Malay Thakershi <mthakershi@gmail.com> wrote:

2013-03-21 16:03:50.795593 [WARNING] sofia_reg.c:2376 Can't find user [504@IP.IP.IP.IP]

You must define a domain called 'IP.IP.IP.IP' in your directory and add a user with the id="504" attribute

and you must configure your device to use the proper domain in it's authentication credentials.

That means there is a phone on your LAN that is trying to register as user (extension) 504, but you haven't created a directory entry for that user in the directory/default/ folder. I.e. it means "unknown user".

Steve