Zend certified PHP/Magento developer

How to fix update error “Clearsigned file isn’t valid, got ‘NOSPLIT’ (does the network require authentication?)”?

Suddenly sudo apt update is not working anymore on my Ubuntu 18.04.6 machine. I get the following error:

Hit:1 https://download.docker.com/linux/ubuntu bionic InRelease
Get:2 http://us.archive.ubuntu.com/ubuntu bionic InRelease
Err:2 http://us.archive.ubuntu.com/ubuntu bionic InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:3 http://us.archive.ubuntu.com/ubuntu bionic-security InRelease
Err:3 http://us.archive.ubuntu.com/ubuntu bionic-security InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease
Err:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Reading package lists... Done
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://us.archive.ubuntu.com/ubuntu bionic InRelease' is not signed.
E: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic-security/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://us.archive.ubuntu.com/ubuntu bionic-security InRelease' is not signed.
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: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease' is not signed.
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.

My /etc/apt/sources.list:

###### Ubuntu Main Repos
deb http://us.archive.ubuntu.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic main restricted universe multiverse

###### Ubuntu Update Repos
deb http://us.archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://us.archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe multiverse

My /etc/resolv.conf:

nameserver 1.1.1.1

I have tried changing the repository mirror to no luck. I tried running sudo apt update from within an Ubuntu docker image and the same error comes out. Would this mean that this is a network issue? Or I can still do/check something?

Thanks!