Hello guys ,facing this error while updating. A beginner and a newbie here so please guide me
===========================
Install Updates Error log
============ Log ===========
Hit:1
http://us.archive.ubuntu.com/ubuntu focal InRelease
Get:2
http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:3
http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [101 kB]
Get:4
http://security.ubuntu.com/ubuntu focal-security InRelease [109 kB]
Hit:5
http://archive.canonical.com/ubuntu focal InRelease
Err:6
http://repo.linuxliteos.com/linuxlite emerald InRelease
Temporary failure resolving 'repo.linuxliteos.com'
Err:7
https://deb.opera.com/opera-stable stable InRelease
Temporary failure resolving 'deb.opera.com'
Err:8
http://dl.google.com/linux/chrome/deb stable InRelease
Temporary failure resolving 'dl.google.com'
Err:9
https://linux.teamviewer.com/deb stable InRelease
Temporary failure resolving 'linux.teamviewer.com'
Err:10
http://packages.microsoft.com/repos/edge stable InRelease
Temporary failure resolving 'packages.microsoft.com'
Err:11
https://packages.microsoft.com/ubuntu/18.04/mssql-server-2019 bionic InRelease
Temporary failure resolving 'packages.microsoft.com'
Err:17
http://packages.microsoft.com/repos/vscode stable InRelease
Temporary failure resolving 'packages.microsoft.com'
Get:12
http://net.domain.name/ppa.launchpad.net//nilarimogard/webupd8/ubuntu focal InRelease
Err:12
http://net.domain.name/ppa.launchpad.net//nilarimogard/webupd8/ubuntu focal InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:13
http://net.domain.name/ppa.launchpad.net//noobslab/apps/ubuntu focal InRelease
Err:13
http://net.domain.name/ppa.launchpad.net//noobslab/apps/ubuntu focal InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:14
http://net.domain.name/ppa.launchpad.net//slimbook/slimbook/ubuntu focal InRelease
Err:14
http://net.domain.name/ppa.launchpad.net//slimbook/slimbook/ubuntu focal InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:15
http://net.domain.name/ppa.launchpad.net//xuzhen666/gnome-mpv/ubuntu focal InRelease
Err:15
http://net.domain.name/ppa.launchpad.net//xuzhen666/gnome-mpv/ubuntu focal InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:16
http://net.domain.name/ppa.launchpad.net//yannubuntu/boot-repair/ubuntu focal InRelease
Err:16
http://net.domain.name/ppa.launchpad.net//yannubuntu/boot-repair/ubuntu focal InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Reading package lists...
E: The repository '
http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu focal InRelease' is no longer signed.
E: Failed to fetch
http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu/dists/focal/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository '
http://ppa.launchpad.net/noobslab/apps/ubuntu focal InRelease' is not signed.
E: Failed to fetch
http://ppa.launchpad.net/noobslab/apps/ubuntu/dists/focal/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository '
http://ppa.launchpad.net/slimbook/slimbook/ubuntu focal InRelease' is no longer signed.
E: Failed to fetch
http://ppa.launchpad.net/slimbook/slimbook/ubuntu/dists/focal/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch
http://ppa.launchpad.net/xuzhen666/gnome-mpv/ubuntu/dists/focal/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository '
http://ppa.launchpad.net/xuzhen666/gnome-mpv/ubuntu focal InRelease' is no longer signed.
E: Failed to fetch
http://ppa.launchpad.net/yannubuntu/boot-repair/ubuntu/dists/focal/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository '
http://ppa.launchpad.net/yannubuntu/boot-repair/ubuntu focal InRelease' is no longer signed.