1. Network problems
Change the WIFI connected to the computer to the hotspot connection of the mobile phone
2. Mirror source problem
Use the latest mirror source to download updates:
You can refer to the following method to obtain it:
Then choose manual replacement or command replacement. Generally, you can directly copy the original .list file and save it somewhere else.
Manual replacement, use gedit to edit and open file commands:
sudo gedit /etc/apt/sources.list
Just select all, overwrite and paste, and save.
If your computer prompts for permission issues, you can grant root permissions:
sudo su
Then update again:
apt-get update