why is this happening?

[samlovr]

[vivek006]

Try inserting another sim on sim slot1 and check if it works.

[samlovr]

actually it doesn't happen instantly after installing the SIM.....phone runs ok 2-3 days then it suddenly happens..

[rockyyyyy1]

I am facing the same problem

[undercover]

I too have the same problem but the sim is working fine even after this

[ArjitKumarSingh]

it's phone problem not the sim. it had happened long time ago with my dad's phone too and that phone was also of Samsung. phone is not able to register the sim on the network after regaining the lost network signal.