@Annalisa
A few things to try:
To fix it quickly, turn on Airplane Mode for 15 seconds, then off. If it persists, turn off your phone, remove the SIM tray, gently wipe the SIM chip with a clean cloth, and reinsert it securely.
Also check for software updates for your phone and also reset the network settings.
__________________________________________________________________________________________
If someone has helped you then please click on the LIKES button in their post.
If you need help please provide as much information as you can
