[gravitypdf]shortcode outside of Gravity Forms AND don’t pass the entry ID to the shortcode or the page.
The most common occurrence is when using Gravity Forms Page Confirmation (which redirects a user to an existing WordPress page). If this occurs, please follow our guide for using the shortcode with the Page Confirmation.
If you want to use the shortcode outside of Gravity Forms entirely you need to include the
entry attribute with the shortcode so Gravity PDF knows what entry is being generated.