Error on sudo apt-get update, 404 Not Found

Upon entering sudo apt-get update in terminal, the following error is given:

Reading package lists... Done
W: The repository 'http://dl.bintray.com/aluxian/deb stable Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://dl.bintray.com/aluxian/deb/dists/stable/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

As the error message indicates, there is a problem with this particular repo.

Go to System Settings->Software & Updates->Other Software and unclick (or delete) the offending repo(s).

sudo apt-get update should now work.