From the minimap in the screenshot, it doesn't even look like you're facing the right objective NPC. Sure you didn't already talk to that one and you still need to find the last?

Should be able to abandon the quest still and retry, if nothing else? You may be able to keep track in the chat log of which NPCs you've talked to, to confirm you're hitting all 4. (assuming since you've relogged, you won't be able to check for that now)