> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.popup-builder.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# FAQ: Why Do I Get an Error When Activating The Extension/Bundle I purchased?

# ${color}[#225fec](Question: )

Getting the following error when trying to install the single extension or a bundle:

To enable  ‘’name of the extension, for example, Popup Builder Subscription Plus’’ extension/Bundle you need to activate the Popup Builder plugin.


# ${color}[#ff8000](Answer: )

The error appears when you are trying to install and activate the pro version of the plugin before having the core version of the plugin installed and activated on the website.

Please, follow the article below to install a free version of the plugin.

[How to Install the Popup Builder Plugin](/en/article/how-to-install-the-popup-builder-plugin-1hoof9z/)