Joke Collection Website - Blessing messages - What does the validity period of SMS set mean?

What does the validity period of SMS set mean?

Usually, SMS is valid for 24 hours.

In other words, when the other party can't accept short messages because the phone is turned off or the mailbox is full, the short messages will be stored in the short message gateway. But the validity period is 24 hours. If the recipient accepts successfully within 24 hours, the operator will charge the SMS fee. Otherwise, there is no charge.