Ubuntu sudo apt get update 404 Not Found problem - Kraft2k/py_info_inv GitHub Wiki

Most of the repositories and PPAs in your sources.list are no longer available and are throwing errors. I'd recommend restoring the default repositories.

First, restore the default repositories using these commands:

mkdir ~/solution
cd ~/solution/

vim sources.list

deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

deb http://archive.canonical.com/ubuntu focal partner
deb-src http://archive.canonical.com/ubuntu focal partner


sudo sed -i "s/focal/$(lsb_release -c -s)/" ~/solution/sources.list
sudo rm /etc/apt/sources.list
sudo cp ~/solution/sources.list /etc/apt/sources.list

Remove all the PPAs in your system:

sudo mv /etc/apt/sources.list.d/* ~/solution

Update the repositories:

sudo apt update

Now there should be no errors.