Why can't someone reply after sending a text message?

1, first make sure that not everyone or just friends received it. (1) If it's just a friend who can't receive it, it's recommended that the other party check whether the phone is down or turned on interception. ② If you can't receive all the messages sent to your friends, please check whether the number of the SMS center is correct and try to set it again. 2. If all the above operations fail, replace the mobile phone card with another mobile phone and try to confirm whether it is a mobile phone or a sim card. 3. Contact the mobile phone seller for the reason of mobile phone, and contact the mobile phone operator for the reason of sim card.