I'm not experienced enough with operation systems and I have a common issue that I looked for a solution but no one is valid.
when I run sudo apt update
, I get the following error:
When I tried to install certbot (http://ppa.launchpad.net/certbot/certbot/ubuntu) in my Ubuntu 20.04, I added a repository so I can download it, but later the OS tell me that "Updating from such a repository can't be done securely, and is therefore disabled by default"
I don't remember how I added it, but it's clearly the solution is remove it from that "package lists". I spent hours looking for a solution but none is valid, why is no one did a clear explanation on how to add/remove a repository from "package lists" ?
can anyone write a valid answer so anyone have this issue will directly find a valid solution for different repositories ?