How should I solve Ubuntu 20.04 update errors? [migrated]
I have problems when I try to update Ubuntu 20.04 , when I run sudo apt update to update, I get this output:
sudo apt-get update Err:1 http://security.ubuntu.com/ubuntu focal-security InRelease Could not resolve 'security.ubuntu.com' Hit:2 http://us.archive.ubuntu.com/ubuntu focal InRelease Hit:3 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease Hit:4 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease Ign:5 http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal InRelease Err:6 http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal Release 404 Not Found [IP: 185.125.190.80 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.
I tried sudo rm -rf/var/lib/apt/lists/* and then sudo apt clean and then sudo apt update, after running these, when I try to update again it gives me some errors at the end, also when I try to add mrazavi/openvas repository, it gives me this error when I press enter to add the repository:
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease Hit:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease Ign:4 http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal InRelease Err:5 http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal Release 404 Not Found [IP: 185.125.190.80 80] Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease Reading package lists... Done E: The repository 'http://ppa.launchpad.net/mrazavi/openvas/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.
how should I solve these issues? should I use VPN?
