4s sends a text message, but the other party can't receive it.

It is probably a network failure, and the information may stay in the information center during transmission. You can't get it if the network signal is not good. If other mobile phones can send it out and others can receive it, it is that there is something wrong with the 4S settings. You can call your operator. If it still doesn't work after debugging, call Apple Customer Service to see if there is a hardware problem.