Theme Activation is a new step which is required since Boombox Version 2. That means that you need to verify your purchase for the theme and enter purchase code for theme. Besides verifying purchase theme activation unlocking some core features for the theme which are required for theme proper work, such as Boombox Demo Importer, WPQUADS PRO plugin and others.
You just need to follow simple steps instructions under the Dashboard▸ Appearance▸ Boombox Activation.
You need to be logged-in in to your Envato account and the need to generate Envato Token with specific permissions. After having token, need to paste token in Dashboard▸ Envato Market ▸ Settings ▸ Token and click on Save Changes and that’s it. If you have purchased Boombox theme with your own Envato account then no need to create Single Use OAuth Personal Tokens.
For more information about its configuration, please read this article: “How To Automatically Update WordPress Themes with the Envato Market Plugin”.