Apple SMS can't send a pig's expression.

The message was sent successfully, but someone else's mobile phone refused to receive it. Charge as usual, indicating that the delivery was successful, but the receipt received was a failure.

The other party's mobile phone is turned off, or there is no signal, and the short message sent is not received by the other party, but if the time exceeds the validity period of the short message set by the other party, it will also prompt that the sending is successful, but the receipt received is failed.