Authelia supports Time-base one-time password generated by apps like Google Authenticator.
After having successfully completed the first factor, select One-Time Password method option and click on Not registered yet? link. This will send you an e-mail to confirm your identity.
NOTE: If you’re testing Authelia, this e-mail has likely been sent to the mailbox available at https://mail.example.com:8080/
Once this validation step is completed, a QRCode gets displayed.
You can then use Google Authenticator to scan the code in order to register your device.
From now on, you get tokens generated every 30 seconds that you can use to validate the second factor in Authelia.