Package 'libtinfo5' has no installation candidate

Question

I am trying to install a libtinfo5 on Ubuntu. So that I can install GHCUP and program with Haskell/Plutus

Does anyone know how to resolve this error?

ubuntu@ubuntu:~$ sudo apt-get update
Ign:1 cdrom://Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1) focal InRelease
Hit:2 cdrom://Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1) focal Release
Get:4 https://cli.github.com/packages stable InRelease [3743 B]                                                                                                                           
Err:4 https://cli.github.com/packages stable InRelease                                                                                                                                    
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C99B11DEB97541F0
Get:5 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]                                                                 
Hit:6 https://updates.signal.org/desktop/apt xenial InRelease                                                                                                           
Hit:7 http://archive.ubuntu.com/ubuntu focal InRelease                                                     
Get:8 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]              
Hit:9 http://dl.google.com/linux/chrome/deb stable InRelease                                    
Hit:10 http://packages.microsoft.com/repos/code stable InRelease
Reading package lists... Done            
W: GPG error: https://cli.github.com/packages stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C99B11DEB97541F0
E: The repository 'https://cli.github.com/packages stable InRelease' is not signed.
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.
ubuntu@ubuntu:~$ sudo apt-get install libtinfo5
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package libtinfo5 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'libtinfo5' has no installation candidate
ubuntu@ubuntu:~$ sudo apt-get install -y libtinfo5
Reading package lists... Done
Building dependency tree

Reading state information... Done
Package libtinfo5 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'libtinfo5' has no installation candidate

Answer 1

At first you have to fix the GPG problem with GitHub CLI repository by using commands below:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-key C99B11DEB97541F0

Then disable cdrom source by editing /etc/apt/sources.list by text editor directly or by using Software & Updates (software-properties-gtk) application.

Then add the universe repository pocket to the system by the same application or by using command

sudo add-apt-repository universe

And finally update package lists and install needed package:

sudo apt-get update
sudo apt-get install libtinfo5