I have tried to do apt-get update in my ubuntu system and has got the following error:
Please help
Hit:17 https://packagecloud.io/slacktechnologies/slack/debian jessie InRelease
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu artful 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.