This problem occurs because of wifi
1. Enter the command in the terminal:
rfkill list all
Check the status of the current wifi switch, it may be soft block or hard block
use command
rfkill unblock all
Unlock them all.
2. Enter the /etc/modprobe.d/ folder to create a .conf file, and add the keywords that affect the wireless wifi switch to the blacklist. Each model and brand is different. On some Lenovo computers, it is ideapad_laptop, and on other computers, it may be another name.
sudo gedit /etc/modprobe.d/ideapad.conf
Type in the first line after opening the file
blacklist ideapad_laptop
Save and close before executing
sudo modprobe -r ideapad_laptop
After restarting, the wifi in the upper right corner is ready to use.