Send a short message to a person, and after a few days, the information status report comes back to show that the information transmission failed, but the other party did not stop. What's going on her

Send a short message to a person, and after a few days, the information status report comes back to show that the information transmission failed, but the other party did not stop. What's going on here? Hello, landlord!

This situation may be that when the other party shuts down, the information will remain on the server for a period of time. If the other party is still not turned on during this period, or is always in a state of no service, the information will stop being saved, that is, the information transmission fails; Or when you send a message, the signal is unstable and the message is damaged, or when the other party receives the message, the message is lost and damaged because of the signal problem.