SIP Registration

I have setup asterisk 11 in ubuntu 14.04.1. i am facing issue regarding sip registration. I had used asterisk GUI for creating users,dialplan etc.

sip account successfully registered if i register via same subnet ip.

eg my server ip: and client ip : [ sip registered successfully]

[b]but i am not able to login via different subnet ips.

server ip: client ip : [sip registration failed] [/b]

plz help me or suggest solution for this .
my firewall ports are open for asterisk requirements.

Asterisk GUI is not supported unless your supplier supports it. It is several years past end of life.

Actually, not GUI is supported on these forums.

Its not the issue related to asterisk gui. I can create users without help of asterisk gui.
I want to reasons why my sip registering failed for different subnet client ip.