Since the introduction of the new account system in November 2021, you no longer need an "old-school" Licence Key to activate Hindenburg.
All you need now is the email address you used to create your account and your password.
To activate Hindenburg, do the following:
Go to the top menu:
Apple: Hindenburg / Manage My Account
Windows: Help / Manage My Account
Here you choose Sign In Account.
Input your account Email & Password.
Hindenburg Support Team
Facebook: Hindenburg News