I am getting this error whenever I try to:
sudo apt-get update
my-pc@my-pc:~$ sudo apt-get update
[sudo] password for my-pc:
Ign:1 http://ppa.launchpad.net/ondrej/mysql-5.6/ubuntu bionic InRelease
Hit:2 http://pk.archive.ubuntu.com/ubuntu bionic InRelease
Ign:3 http://archive.ubuntu.com/ubuntu trusty InRelease
Get:4 http://pk.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Hit:5 http://archive.ubuntu.com/ubuntu trusty Release
Hit:6 http://ppa.launchpad.net/ondrej/php/ubuntu bionic InRelease
Ign:7 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 InRelease
Hit:8 http://security.ubuntu.com/ubuntu bionic-security InRelease
Ign:10 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 InRelease
Hit:11 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 Release
Err:12 http://ppa.launchpad.net/ondrej/mysql-5.6/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Hit:14 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 Release
Hit:15 https://download.stackify.com/deb stable InRelease
Hit:17 https://repo.skype.com/deb stable InRelease
Get:18 http://pk.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/ondrej/mysql-5.6/ubuntu bionic 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.
my-pc@my-pc:~$
How can I fix this?
Here is an output of /etc/apt/sources.list :
# deb cdrom:[Ubuntu 18.04.4 LTS _Bionic Beaver_ - Release amd64 (20200203.1)]/ bionic main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://pk.archive.ubuntu.com/ubuntu/ bionic main restricted
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://pk.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://pk.archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic universe
deb http://pk.archive.ubuntu.com/ubuntu/ bionic-updates universe
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://pk.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://pk.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://pk.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src http://pk.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner
deb http://security.ubuntu.com/ubuntu bionic-security main restricted
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse
deb http://archive.ubuntu.com/ubuntu trusty universe
# deb-src http://archive.ubuntu.com/ubuntu trusty universe
# deb-src http://archive.ubuntu.com/ubuntu trusty universe
