In Plezi, you cannot delete a piece of content or a landing page once this is the starting point for creating a contact. In fact, this leads to numerous changes, particularly for your contacts’ history and scores.
If you no longer want to use a white paper, simply delete the form from your website and remove access to the associated landing page.
You can also remove the contacts created by this piece of content, which will then become deletable.
To make sure certain articles don’t fail to load automatically in Plezi, you must exclude them from your RSS feed. To do this, use this type of plugin: https://fr.wordpress.org/plugins/stealth-publish/#description.