Hi Nilesh!
Hmmm... this is odd, but may be down to the SIM. I've just sent you an email regarding another query (Content Control). If you can explain this problem on that email, we'll be able to check the SIMs registration details in case it need extra provisioning. It could be that it lacks an access point (APN) or needs refreshing with the network.
Hope to hear back from you soon,
Daz
eForum Team