Blizzard has posted hotfixes for today which fixes Castle Nathria LFR being queuable.
Here you’ll find a list of hotfixes that address various issues related to World of Warcraft: Dragonflight, Wrath of the Lich King Classic, Burning Crusade Classic and WoW Classic. Some of the hotfixes below take effect the moment they were implemented, while others may require scheduled realm restarts to go into effect.