On this page: https://artixlinux.org/download.php
It says: The official ISOs below are signed with PGP key 0xB886B428.
0xB886B428 is supposed to be a link but I think it's broken. ( curl: (6) Could not resolve host: keys.gnupg.net )
I think I managed to correctly verify the ISO by using: http://keyserver.ubuntu.com/pks/lookup?search=0xA574A1915CEDE31A3BFF5A68606520ACB886B428&fingerprint=on&op=index
But I thought you might want to look into the broken link on the download page.
Any valid keyserver will do, for example: http://pgp.surf.nl/pks/lookup?search=0xB886B428&fingerprint=on&op=index
The likely takedown of keys.gnupg.net could be related to GDPR requests:
https://sks-keyservers.net/
See also:
https://sks-keyservers.net/status/
https://bugs.archlinux.org/task/71078
Also the recommendation on not using keyservers for key discovery:
https://lists.gnupg.org/pipermail/gnupg-devel/2021-June/034889.html
Thanks for reporting, fixed using another keyserver.