If you’re a level 70 Druid and you’re playing the latest expansion, to unlock the Druid Hall quests, you need to delete an item from one of the quests at the beginning of TWW.
wowhead item=227669/teleportation-scroll
If you delete this item, reload the interface and wait, the NPC Archdruid Hamuul Runetotem will appear.
I’m leaving here this information here because I had a discussion with the GMs. I haven’t received any help from them.