Hi
@kmlynarova79 We apologize for the inconvenience this is causing you. Can you make sure that cellular data is enabled in settings? Also, since you just came back from traveling, did you change any data settings like APN? If all the settings remain the same please try:
Inserting/ testing with another SIM card
Update your device to the latest firmware if you haven't done so already
Try to boot in safe mode to see if the SIM card works without interaction of a third-party app
Check if the SIM tray is damaged.