problem in network connection

[ani_]

i am using xperia m since last 8 months, but now after getting the latest update calling Android 4.3 in the network signal area there is a red cross. the sim is working allright in other phone but not in xperia m. if any body have answer to my problem please suggest what to do.

[Hampus]

Hi and welcome to the community! Since you're new please be sure that you have checked out our Discussion guidelines.

Have you tried another SIM-card in your phone to see if you experience the same behaviour? Otherwise, if this happened after a software update, I suggest that you perform a software repair via PC Companion to exclude software related problems:
http://www.sonymobile.com/global-en/tools/pc-companion/

In PC Companion you press start on Support Zone > Start on Update the phone/tablet software > Repair phone/tablet (the blue clickable link in the message) > Follow these steps without having your device connected to the PC.

Follow the instruction that appears in the program and do not connect your device until this guide tells you how to connect it.