Why did Apple send a text message to Huawei showing that there was no delivery?

Network problems or the reason for the other party's shutdown.

When the network status is poor, sending a short message will prompt that it was not delivered, indicating that the transmission failed. In addition, if the other party's mobile phone is turned off, it can't receive messages.

By checking whether the short message has been delivered, you can better understand whether your information has been conveyed to the other party, which is conducive to further work exchanges.