How can I fix my iPhone SIM activation issue after restoring it?

My phone sim was not working on the previous version of IOS, and it wasn't updating it got stuck on verifying and taking too much time. So I plugged it to the laptop connected it with Itunes and restored it completely. But not it is saying that it is unable to activate and showing me the option to shut my phone down. Any help would be much appreciated

[Re-Titled by Moderator]