Hi ZlyFox! Excuse me, I think you need to ping inside one of the pings of the artist. This type of ping only works if the artist visits your profile or sees you from their feed while subscribed to you.

I think only users subscribed to your notifications can see these types of pings in their feed without going to your profile (I made that mistake once :c), so I suggest you to go to the user's profile and post this ping there BUT within one of their notifications. That way, the user will even receive an email :)