Why can I receive messages from others? If I reply to them, no one else will receive it.

The mobile phone has no networking and flight mode.

1, the mobile phone is not connected to the internet: when sending a text message to others, the text message will be transmitted to the other party's mobile phone by radio waves. If the other party's mobile phone is not connected to the internet, they can't receive these messages.

2. Flight mode: The other party's mobile phone is in flight mode, and it is set to block strangers' short messages, which also makes it impossible to receive short messages.