sudo apt-get update
Get:1 http://dl.google.com/linux/chrome/deb stable InRelease [1,811 B]
Err:2 http://us.old-releases.ubuntu.com/ubuntu focal InRelease
Could not resolve 'us.old-releases.ubuntu.com'
Ign:3 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu focal InRelease
Err:4 http://us.old-releases.ubuntu.com/ubuntu focal-updates InRelease
Could not resolve 'us.old-releases.ubuntu.com'
Err:5 http://us.old-releases.ubuntu.com/ubuntu focal-backports InRelease
Could not resolve 'us.old-releases.ubuntu.com'
Ign:6 http://old-releases.ubuntu.com/ubuntu focal-security InRelease
Err:7 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu focal Release
404 Not Found [IP: 91.189.95.85 80]
Err:8 http://old-releases.ubuntu.com/ubuntu focal-security Release
404 Not Found [IP: 91.189.88.247 80]
Reading package lists... Done
E: Release file for http://dl.google.com/linux/chrome/deb/dists/stable/InRelease is not valid yet (invalid for another 29min 28s). Updates for this repository will not be applied.
E: The repository 'http://ppa.launchpad.net/danielrichter2007/grub-customizer/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.
E: The repository 'http://old-releases.ubuntu.com/ubuntu focal-security 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.
有什么想法吗？Ubuntu Mate，20.04.2 LTS