If you fail to kill Lord Retro, how long do you need to wait before you can retry?

Question

If I fail to kill lord retro and get kicked from the quest how long do I have to wait to be able to retry it

Answer 1

Succeeding or failing, either way it will be count as an attempt and you'll be able to go again only after 20h (the same applies to all 10 mini-bosses).