try to unlock... the fone is locked on same network and the code is enter 9/10 times incorectly, that is the problem with your phone.
use Ns Pro if you have or another box for unlocking... for z-series you must to haver z*** adapter it's not easy to unlocking if you are begginer without profesional programs.
this is freeware for unlocking but i don't have a tutoraial for this software:
LUCIFER_SAMSUNG_TOOL_V_1[1].03.
good luck
my frend
