Recently working on a Drupal site, creating new paragraph types as you do… While creating pages and testing the paragraphs, I got the following error: This entity (paragraph: ID) cannot be referenced. This was the first time I ever saw this error.
What I discovered was I accidentally unselected the paragraph type from the “Reference type” section on the entity reference revision field.
This can happen on any entity reference field not just a paragraph field.
If you create a page and reference an entity or create a paragraph. If the content or paragraph type is unselected from the reference type section. The next time you save the form you’ll get the error.
How to Replicate Error with Paragraphs
1. Create two paragraph types (can be anything):
2. Add Paragraph field to “Basic page” content type.
3. Create a page and add the Content and View paragraph type.
4. Edit the paragraph field, (Structure -> Content types ->Basic page -> Manage fields) and unselect View.
5. Go back to the page with the created paragraph and save the page. Then you should see the error message.
Just to summarize, if you see “This entity (paragraph: ID) cannot be referenced” or “This entity (node: ID) cannot be referenced”. Then it means that the one of your entity reference (revision) fields can no longer reference the content type or paragraph type. You’ll need to figure out which field is causing the issue and select the correct bundle from the “Reference type” section.