Trying to install MX-Snapshot on SolydX.

Hi,

Trying to install MX-Snapshot on SolydX.
The procedure I am following to install this tool leads me to some problems that I do not know how to solve.

[From Debian Forum: https://forums.debian.net/viewtopic.php?f=16&t=146083 ]

Please, read the thread/link above while following these steps:

Code:root@SolydXK:~# nano /etc/apt/preferences.d/mxlinux
root@SolydXK:~# nano /etc/apt/sources.list.d
root@SolydXK:~# nano /etc/apt/sources.list.d/mxlinux.list

root@SolydXK:~# LANG=C apt update
Hit:1 http://deb.debian.org/debian buster InRelease
Hit:2 http://deb.debian.org/debian buster-updates InRelease
Hit:3 http://security.debian.org buster/updates InRelease
Get:4 http://mxrepo.com/mx/repo buster InRelease [19.9 kB]
Ign:5 http://repo.vivaldi.com/stable/deb stable InRelease
Hit:6 http://repo.vivaldi.com/stable/deb stable Release
Hit:7 http://download.opensuse.org/repositories/home:/hawkeye116477:/waterfox/Debian_9.0 InRelease
Hit:8 http://download.opensuse.org/repositories/home:/stevenpusser/Debian_10 InRelease
Hit:9 http://download.opensuse.org/repositories/Emulators:/Wine:/Debian/Debian_10 ./ InRelease
Err:4 http://mxrepo.com/mx/repo buster InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 276ECD5CEF864D8F
Hit:11 https://repository.solydxk.com solydxk-10 InRelease
Reading package lists... Done
W: GPG error: http://mxrepo.com/mx/repo buster InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 276ECD5CEF864D8F
E: The repository 'http://mxrepo.com/mx/repo buster 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.

root@SolydXK:~# gpg --keyserver keyserver.ubuntu.com --recv-keys $mx_gpg_key
gpg: creado el directorio '/root/.gnupg'
gpg: caja de claves '/root/.gnupg/pubring.kbx' creada

root@SolydXK:~# LANG=C gpg -a --export $mx_gpg_key | apt-key add -
gpg: WARNING: nothing exported
gpg: no se han encontrados datos OpenPGP validos
root@SolydXK:~#*can't find OpenPGP data

Thank you very much for any guidance.