Unable to stake using Lunie.io

Why am I unable stake ATOM tokens using Lunie.io? I am being asked to touch my security key. What security Key? Finally, I get a the following message : "Delegating failed: signing failed. Unknown status code. Undefined.

Did you checked [Delegators] Cosmos & Tendermint Guides, Wallets, Explorers & Tools ?

You can find dozen of step by step guides there

It asks you to use one of the Ledger keys that could be purchased from https://www.ledger.com/

Thanks for the reply, but could you be a little more specific. what ledger keys? I went to that website, but I can not see any keys.

Keys are just an other way to say “hardware module”. Check the “Products” section on their website.