no service in my iphone 3gs after restored ios 6.1.6

firstly i forget my passwork in order to unlock my password i made a restore to ios 6.1.6
my password unlocked but i got a big problem
the sim card doing searching…. and give me no service
i tired of search in a lier ways in youtube
i spend hole the day to try
i jailbreak it and installed cydia and installed ultrasnow
but it didn’t work
still no service and searching

what i have to do for solving this issue