Update Issue - Never Seen This Before

[lc6529]

===========================
Install Updates Error log
===========================
Install Updates could not fetch the package cache information lists.
Go to https://www.freecinema2022.gq/forums/ and paste the log below into a new or existing thread for assistance.

============ Log ===========

Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:3 https://ocean.surfshark.com/debian stretch InRelease
Hit:4 http://packages.microsoft.com/repos/edge stable InRelease
Get:5 http://security.ubuntu.com/ubuntu focal-security InRelease [370 B]
Err:5 http://security.ubuntu.com/ubuntu focal-security InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Hit:6 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:7 https://deb.opera.com/opera-stable stable InRelease
Hit:8 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:9 http://archive.canonical.com/ubuntu focal InRelease
Hit:10 http://mirror.alpix.eu/linuxliteos emerald InRelease
Hit:11 https://packages.bluemail.me/repos/debian ./ InRelease
Get:12 https://repo.protonvpn.com/debian stable InRelease [2,519 B]
Err:12 https://repo.protonvpn.com/debian stable InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 71EB474019940E11
Reading package lists...
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/.../InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://security.ubuntu.com/ubuntu focal-security InRelease' is no longer signed.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://repo.protonvpn.com/debian stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 71EB474019940E11