![我想安装 Docky。如何删除“Err:5 http://ppa.launchpad.net/docky-core/stable/ubuntu focal Release 404 Not Found [IP: 91.189.95.85 80]”？](https://linux22.com/image/941085/%E6%88%91%E6%83%B3%E5%AE%89%E8%A3%85%20Docky%E3%80%82%E5%A6%82%E4%BD%95%E5%88%A0%E9%99%A4%E2%80%9CErr%3A5%20http%3A%2F%2Fppa.launchpad.net%2Fdocky-core%2Fstable%2Fubuntu%20focal%20Release%20404%20Not%20Found%20%5BIP%3A%2091.189.95.85%2080%5D%E2%80%9D%EF%BC%9F.png)
我想在 Ubuntu 20.04 上安装“Docky”，但是每次尝试添加源存储库时，都会收到错误。
这就是我尝试添加存储库的方式：
sudo add-apt-repository ppa:docky-core/stable
结果如下：
Ign:1 http://ppa.launchpad.net/docky-core/stable/ubuntu focal InRelease
Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Hit:3 http://in.archive.ubuntu.com/ubuntu focal InRelease
Err:5 http://ppa.launchpad.net/docky-core/stable/ubuntu focal Release
404 Not Found [IP: 91.189.95.85 80]
Hit:6 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:7 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:8 https://dl.winehq.org/wine-builds/ubuntu focal InRelease
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/docky-core/stable/ubuntu focal 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.
我该如何解决这个错误？