404 Not Found error while running Apt and AppStore EOS Juno

Question

when I open the app store in EOS Juno I am getting these errors:

Failed to Fetch Updates

This may have been caused by external, manually added software repositories or a corrupted sources file.

E: http://packages.mate-desktop.org/repo/ubuntu precise InRelease is not (yet) available (Could not resolve 'packages.mate-desktop.org')
E: http://packages.mate-desktop.org/repo/ubuntu precise InRelease is not (yet) available (Could not resolve 'packages.mate-desktop.org')
E: The repository 'http://ppa.launchpad.net/heathbar/super-wingpanel/ubuntu bionic Release' does not have a Release file.

I have not installed anything, via the AppStore or Apt/Apt-get for a while.

I figured I would run apt get update to fix it, but when i did I got these errors:

    Err:22 http://ppa.launchpad.net/heathbar/super-wingpanel/ubuntu bionic Release 
  404  Not Found [IP: 91.189.95.83 80]
    Err:23 http://ppa.launchpad.net/heathbar/super-wingpanel-daily/ubuntu bionic Release
  404  Not Found [IP: 91.189.95.83 80]
Reading package lists... Done                      
E: The repository 'http://ppa.launchpad.net/heathbar/super-wingpanel/ubuntu bionic 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://ppa.launchpad.net/heathbar/super-wingpanel-daily/ubuntu bionic 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 saw this link, even though it deals with EOS Loki I thought it might work. I ran this with no issues, then I ran sudo apt update again but with the same results. I am currently trying to make EOS look like a mac, so I have an icon them, plymouth theme, and a (in progress) login theme. I tried to install super-wingpanel, but it did not work. I think that is what is throwing issues but I have no idea how to delete this file or if that is what I need to do.

UPDATE

I ran the fix that a-tokarev sugested. It fixed most of my issues but now when I open the AppStore it is throwing this error:

E: http://packages.mate-desktop.org/repo/ubuntu precise InRelease is not (yet) available (Could not resolve 'packages.mate-desktop.org')

I have no idea why this is throwing an error. Apt is also throwing errors when I try to update.

W: Failed to fetch http://packages.mate-desktop.org/repo/ubuntu/dists/precise/InRelease  Could not resolve 'packages.mate-desktop.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.

I can install new packages via apt and I can upgrade, but I cannot update. I can install apps through the AppStore, but every other second it is throwing those errors listed at the top. I am thinking this is an easy fix, but if it is not I probably will back up all my files and use a fresh install. Any help is appreciated. Thanks!

Answer 1

PART 1

As super-wingpanel software appears to be quite old, no wonder its repository (PPA) doesn't have proper release file - i. e. the version, that's been specifically compiled for Ubuntu 18.04 (codename 'bionic', on which elementary OS 5 is based).

To fix this error (i. e. to stop super-wingpanel's further attempts to get non-existent updates, while keeping it installed on your system), remove super-wingpanel's PPA from your system list. To do it, execute:

sudo add-apt-repository --remove ppa:heathbar/super-wingpanel

and then:

sudo apt update

PART 2

The error/warning messages containing packages.mate-desktop.org mean that apt-get update can't fetch (download) the list of packages, required to update mate-desktopsoftware.

As this error is obviously an external server's IP issue and not elementary OS' fault, you have two options to fix it.

Option 1. If you don't use mate-desktop for anything, uninstall it.

Option 2. If you still use it, you can comment out its update URLs, so apt-get update won't use them during the update process. In this case, if mate-desktop devs will eventually fix their package server's IP issue, you can uncomment the URLs and update your mate-desktop software.