Why does the Nokia 3230 I use always prompt "sending delay" instead of "delivered" after sending SMS?

Here's the thing. When you send a message, the message is sent to the message center first, and then sent to the person you want to send by the message center. When it has been delivered by the SMS center, the SMS center will send you a message, and the sending report of your mobile phone will show that it has been delivered.

But there are two situations:

First, if the network of the object you want to send a short message is blocked and the short message center can't send a short message to the object, then the short message center system will resend it after a certain period of time, so your mobile phone will display that sending is suspended because there is no feedback information during this period. In this case, the delay in sending is really that the other party did not receive it.

Second, if your network is blocked, the information fed back by the SMS center can't reach your mobile phone, so your mobile phone still shows that sending is suspended, but in fact your short message has been delivered to the other party's mobile phone, which may even happen. I have received the reply from the other party, but it still shows that sending is suspended.

If your message cannot be sent to the SMS Center, it will display "Sending failed, delayed sending" instead of sending suspended.

So the landlord can judge the situation by himself.

But as far as my experience is concerned, the reliability of SMS reporting is still relatively high ~