I have tried installing Unity2d/3d via the terminal in a way to become more comfortable around the usage of the terminal and have across an issue where when I try and update via the terminal it brings up and error for unity2d/3d. I have copied on what is output once I have used sudo apt update:
Hit:1 http://gb.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://gb.archive.ubuntu.com/ubuntu focal-updates InRelease Hit:3 http://ppa.launchpad.net/git-core/ppa/ubuntu focal InRelease Hit:4 http://gb.archive.ubuntu.com/ubuntu focal-backports InRelease Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease Get:5 https://hub-dist.unity3d.com/artifactory/hub-debian-prod-local stable InRelease [2,739 B] Err:5 https://hub-dist.unity3d.com/artifactory/hub-debian-prod-local stable InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BE3E6EA534E8243F Reading package lists... Done W: GPG error: https://hub-dist.unity3d.com/artifactory/hub-debian-prod-local stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BE3E6EA534E8243F E: The repository 'https://hub.unity3d.com/linux/repos/deb 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.
I was using seeing the history on my terminal in the hope that I can see if I have inputted an incorrect command, although i do not see anything wrong I have noticed that I did use the same command twice, would this be reason on why I am getting the above error code?
I am using Ubuntu 20.04.4 LTS 64-bit 3.36.8