How to do four exclamation points of Apple 12 signal?

I used my mobile phone to surf the Internet, and found that some Apple mobile phone signals showed four exclamation points, and I wanted to set my own Apple mobile phone signal as an exclamation point. What about the four exclamation points of Apple 12 signal?

The four exclamation marks of Apple 12 signal How to get the four exclamation marks of Apple 12 signal is because the current network signal is not good, the signal icon will automatically become four exclamation marks, and you can reconnect after restoring the network settings. The specific operation steps are as follows:

1. Click General in the phone settings menu.

2. Click Transfer or Restore iPhone, and then select Restore.

3. Click Restore Network Settings.

This paper takes Apple 12 as an example and applies it to ios 15 system.