Share your experience!
Do you have a MICRO SIM card or did you trimmed a regular SIM card?
try the basic
1. restart the phone
2. remove the SIM card > re-insert the SIM card > check again.
Re-install lollipop with PCC and check again
PC Companion (PCC)
Bridge (for Mac)
Alternatives on How to backup Xperias
http://talk.sonymobile.com/thread/36355