It is possible that the operator (carrier) you are subscribed to experiences technical difficulties (e.g. power outage or network signal booster). Try calling their support team, from another device or via their website, and provide them with all the information they ask you for.
Maybe the operator (carrier) experiences technical difficulties, or carries out a regular maintenance. Wait for no more than 30 minutes. If you still don't get a signal, report the issue to the operator (in the nearest store).
If you haven't payed the last bills, the carrier might have suspended your account. Contact the operator (carrier) or pay a visit to them and pay the bills (if needed).
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.