Ошибки при обновлении apt-get: Ubuntu 16.04

Я пытался выяснить, что происходит, когда я запускаю apt-get update. Я попытался просмотреть файл с исходниками, а также использовать Ubuntu Tweak для очистки списка источников, но ничего не работает.

Когда я запускаю apt-get update, я получаю это:

Reading package lists... Done
N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'https://packages.microsoft.com/repos/vscode stable InRelease' doesn't support architecture 'i386'
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04  Release: The following signatures were invalid: KEYEXPIRED 1496576244
W: The repository 'http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial 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.
W: Failed to fetch http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04/Release.gpg  The following signatures were invalid: KEYEXPIRED 1496576244
E: Failed to fetch http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
W: Some index files failed to download. They have been ignored, or old ones used instead.
W: Duplicate sources.list entry http://packages.microsoft.com/repos/vscode stable Release