Before you enter your Yubikey Unique keys, you need to have your App ID and API Key. Please read the article here.

Once you have your App ID and API Key, please follow these steps:

  1. Go to Shield plugin => Login Guard => 2FA-Yubikey => enable Yubikey Authentication => enter your App ID and API Key (see the screenshot below)
  2. Go to Users => your Profile page
  3. At the bottom of the page you'll see an area where you can input your Yubikey. Simply supply a Yubikey One-Time-Password in the text field and save. (See the screenshot below)

Step 1 screenshot

Step 3 screenshot

Once these are set, the Yubikey functionality is ready to run as your valid 2FA option.