Apple sent a short message without marking the delivery.

1. If the other party is connected to the Internet, they can receive it. If the other party is not connected to the Internet, the imessage you send will automatically send a text message.

2. Maybe you are blocked by the other party;

3. If the other party is not in the service area or turned off, it will be received when it is turned on;

The other party has received it. If the delivery fails, the other party has a mobile phone number, which will be automatically converted into a short message. Without these tips, the delivery was successful.

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Analysis of the specific problem that iPhone can't send and receive SMS:

1, confirm that the signal is normal and close the flight mode.

2. Check whether the SIM card status is normal.

3. Check whether the send key is displayed in bright color and clickable.

4. If you can't click Send after entering the text, the "Send" button is still gray. Please turn off "Show Subject Bar" in SMS settings.

5. If you send text messages to multiple people and manually enter numbers, please make sure to use line breaks instead of spaces to separate each number.