Comment 30 for bug 2055239

Hello. I'm also running into this problem:

sudo apt update && sudo apt upgrade
Warning: The unit file, source configuration file or drop-ins of apt-news.service changed on disk. Run 'systemctl daemon-reload' to reload units.
Warning: The unit file, source configuration file or drop-ins of esm-cache.service changed on disk. Run 'systemctl daemon-reload' to reload units.
Hit:1 http://us.archive.ubuntu.com/ubuntu noble InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu noble-updates InRelease
Hit:3 http://security.ubuntu.com/ubuntu noble-security InRelease
Hit:4 http://us.archive.ubuntu.com/ubuntu noble-backports InRelease
Hit:5 https://linux.teamviewer.com/deb stable InRelease
Hit:6 https://esm.ubuntu.com/apps/ubuntu noble-apps-security InRelease
Hit:7 https://esm.ubuntu.com/infra/ubuntu noble-infra-security InRelease
Ign:8 https://repository.mullvad.net/deb/stable noble InRelease
Hit:9 https://ppa.launchpadcontent.net/unit193/encryption/ubuntu noble InRelease
Err:10 https://repository.mullvad.net/deb/stable noble Release
  404 Not Found [IP: 45.149.104.1 443]
Reading package lists... Done
W: https://ppa.launchpadcontent.net/unit193/encryption/ubuntu/dists/noble/InRelease: Signature by key 3BFB8E06536B8753AC58A4A303647209B58A653A uses weak algorithm (rsa1024)
E: The repository 'https://repository.mullvad.net/deb/stable noble 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 have no idea what it even means. Any suggestions? Should I even be concerned about this?