What does the exclamation point mean in Apple News?

There is a red exclamation mark on Apple's mobile phone message, because the short message can't be sent. You need to restart the "iMessage" function. The specific operation method is as follows:

Tool: iPhone6s

Operating system: iOS 13.4. 1.

1. In the interface on the desktop, the information icon has an exclamation point.

2. Click the Settings icon on the desktop.

3. Open the phone settings interface and click the information option.

4. Open the information interface and click the switch button in the imessage information bar.

5. At this time, the imessage information bar is light green after being successfully opened.

6. But when you quit the desktop, you can see that the exclamation mark on the SMS of Apple's mobile phone has been removed.