Thumbnail in a view

Problem/Motivation

I need to create a content with a thumbnail that opens with colorbox.
In Preview of the view it works perfectly, but I can't have the thumbnail in the page: https://www.gmpe.it/attivita

Steps to reproduce

- Drupal 10.3.6
- Content type with image field: original image
- View: Image style for content: thumbnail 100x100; Image style for Colorbox: original image

I don't understand where the error is.

Thanks