Update Manager failed to download repository, 401 error

I haven't used my Ubuntu install in about 2 months. I went on last night and first thing I did was update, but I got this message saying it failed to download the repository and to check my connections, even though my internet is fine. Here is the error log:

W:Failed to fetch https://private-ppa.launchpad.net/commercial-ppa-uploaders/multiwinia/ubuntu/dists/precise/main/binary-amd64/Packages  The requested URL returned error: 401
W:Failed to fetch https://private-ppa.launchpad.net/commercial-ppa-uploaders/multiwinia/ubuntu/dists/precise/main/binary-i386/Packages  The requested URL returned error: 401
E:Some index files failed to download. They have been ignored, or old ones used instead.

I noticed that it has the name of Multiwinia in the file path, which is a game I downloaded from the software store roughly 3 months ago. I removed it to see if that would fix the issue, but to no avail.

Any help on the issue would be much appreciated.

Apparently the ppa got added, when you installed the game and now the ppa is broken or suspended. At least that's my best guess. It should be save do remove those repositories from your list. To do so got to:

Software Center -> Edit menu -> Software Sources -> Click the tab Other Sources -> Unselect the ppas in question.

If that doesn't work try to change the download server to the best one:

First three steps from above -> Download from -> Other -> Select Best Server

Software in Ubuntu is installed from package repositories containing a number of packages. This is different from the 'click next' installers in Windows. So, you have removed Multiwinia, but the repositories remain there. But having the repositories there is usually not an issue, the error occurs due to unstable Internet connection or repository issues.

To remove the repository, open Ubuntu Software Center > Edit menu > Software Sources > click the 'Other Software' tab > Uncheck the unwanted repositories with 'multiwinia' in it.

OR

Open a Terminal > type:

sudo gedit /etc/apt/sources.list

Remove these lines: [careful with this file!]

https://private-ppa.launchpad.net/commercial-ppa-uploaders/multiwinia/ubuntu/dists/precise/main/binary-amd64/Packages

https://private-ppa.launchpad.net/commercial-ppa-uploaders/multiwinia/ubuntu/dists/precise/main/binary-i386/Packages

Hopefully this solves your issue.

Edit: There are more repository list files in /etc/apt/sources.list.d folder. For example, Google Chrome repos are in /etc/apt/sources.list.d/google-chrome.list

So, you may look in /etc/apt/sources.list.d for files like multiwinia.list and remove the file. Do take a backup before you delete or edit anything unless you are absolutely sure of what you are doing.