Confirm whether there is a network. I suggest you use it in a place with strong signal. Check whether the account still has telephone charges, and if the balance is insufficient, it needs to be recharged before it can be used; Confirm whether the parameters of the mobile phone have been set; Check whether the USIM card is inserted. If it's plugged in and still doesn't work, I suggest you go to the business hall to check whether the USIM card is faulty or not. Check whether there is something wrong with your mobile phone. I suggest you change your mobile phone for the test. If the traffic is capped, it will also lead to the inability to access the Internet; If the real name registration number is not registered and the real name registration is not completed within the time limit, the service will be suspended; Try shutting down and restarting to search the network.