Finishing An Echo in the Darkness should not be much of an issue, but World of Warcraft: Shadowlands is never without its quirks. Many players are reporting trouble getting this quest to trigger, but there’s a couple options for you to try before worrying about submitting a ticket.
As you begin or continue your story chain in A Fateful Vision or Peering into Darkness, you’ll need to speak to Bolvar Fordragon. The map makes Bolvar easy to find, but what if the opportunity to start the quest never appears? The best option is to leave Oribos and come back. You could take one of the portals to the upper floors, and upon returning, you should have no issue speaking to Bolvar to begin the quest. You can also take advantage of some of your hearthstones if they’re not currently on cooldown.
If you see the quest marker on your map but Bolvar doesn’t have a ‘!’ marker above his head, try the method described above. It’s one of those Blizzard/World of Warcraft quirks that will hopefully get ironed out in one of the upcoming hotfixes over the week. Once you successfully complete An Echo in the Darkness, you can continue on the quest line, and make your way to Torghast to begin The Highlord’s Vision.