I get the following error when installing on an Ubuntu machine.

====================================================
INSTALLING HOMESEER.SH GPG PUBLIC KEY

====================================================
ADDING HOMESEER.SH APT REPOSITORY

====================================================
UPDATING APT REPOSITORIES

Get:1 https://homeseer.sh/download v4 InRelease [4,015 B]
Err:1 https://homeseer.sh/download v4 InRelease
The following signatures were invalid: EXPKEYSIG 5A4CCE990A0C8671 homeseer.sh [email protected]
Reading package lists... Done
W: GPG error: https://homeseer.sh/download v4 InRelease: The following signatures were invalid: EXPKEYSIG 5A4CCE990A0C8671 homeseer.sh [email protected]
E: The repository 'https://homeseer.sh/download v4 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.

INSTALLING PREREQUSITES

Get:1 https://homeseer.sh/download v4 InRelease [4,015 B]
Err:1 https://homeseer.sh/download v4 InRelease
The following signatures were invalid: EXPKEYSIG 5A4CCE990A0C8671 homeseer.sh [email protected]
Hit:2 http://archive.ubuntu.com/ubuntu mantic InRelease
Hit:3 http://security.ubuntu.com/ubuntu mantic-security InRelease
Hit:4 http://archive.ubuntu.com/ubuntu mantic-updates InRelease
Hit:5 http://archive.ubuntu.com/ubuntu mantic-backports InRelease
Hit:6 http://archive.ubuntu.com/ubuntu noble InRelease
Reading package lists... Done
W: GPG error: https://homeseer.sh/download v4 InRelease: The following signatures were invalid: EXPKEYSIG 5A4CCE990A0C8671 homeseer.sh [email protected]
E: The repository 'https://homeseer.sh/download v4 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.
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
mono-complete is already the newest version (6.8.0.105+dfsg-3.4).
mono-devel is already the newest version (6.8.0.105+dfsg-3.4).
mono-vbnc is already the newest version (4.0.1-3).
flite is already the newest version (2.2-6).
chromium-browser is already the newest version (1:85.0.4183.83-0ubuntu3).
aha is already the newest version (0.5.1-3).
ffmpeg is already the newest version (7:6.0-6ubuntu1).
alsa-base is already the newest version (1.0.25+dfsg-0ubuntu7).
alsa-utils is already the newest version (1.2.9-1ubuntu1).
tmux is already the newest version (3.3a-5).
curl is already the newest version (8.4.0-2ubuntu1).
wget is already the newest version (1.21.4-1ubuntu1).
nano is already the newest version (7.2-1).
0 upgraded, 0 newly installed, 0 to remove and 95 not upgraded.
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package 'brltty' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 95 not upgraded.

INSTALLING HOMESEER

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package homeseer 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 'homeseer' has no installation candidate

HOMESEER INSTALLATION COMPLETE

The Homeseer installation files are located at:
/opt/homeseer

Please see https://homeseer.sh for more information.

I just tried a manual installation as per the instructions in the README.

I get an error saying that the public key is not available.

Am I missing something ?

$ wget -qO- https://homeseer.sh/homeseer.gpg | sudo apt-key add -
[sudo] password for frl:          
OK

$ echo 'deb [arch=all signed-by=/etc/apt/keyrings/homeseer.gpg] https://homeseer.sh/download v4 stable' | sudo tee /etc/apt/sources.list.d/homeseer.list
deb [arch=all signed-by=/etc/apt/keyrings/homeseer.gpg] https://homeseer.sh/download v4 stable

$ sudo apt update
Ign:1 http://packages.linuxmint.com una InRelease
Hit:2 http://packages.linuxmint.com una Release                                
Hit:3 http://archive.ubuntu.com/ubuntu focal InRelease                        
Get:4 https://homeseer.sh/download v4 InRelease [4,015 B]                      
Hit:5 http://archive.ubuntu.com/ubuntu focal-updates InRelease                
Get:6 http://archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]      
Hit:8 http://archive.canonical.com/ubuntu focal InRelease                      
Hit:9 http://security.ubuntu.com/ubuntu focal-security InRelease              
Hit:10 https://download.docker.com/linux/ubuntu focal InRelease            
Err:4 https://homeseer.sh/download v4 InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A4CCE990A0C8671
Reading package lists... Done
W: GPG error: https://homeseer.sh/download v4 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A4CCE990A0C8671
E: The repository 'https://homeseer.sh/download v4 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.

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