If you're encountering issues with installing Dropzone on Drupal, an effective solution is to revert to version 2.8.0, as version 2.9.0 has been found to have some problems. To do this, you simply need to update your composer.json file to specify the desired version of the dependencies. Add the following lines to your composer.json under the require section:
"drupal/dropzonejs": "2.8.0",
"drupal/dropzonejs_eb_widget": "2.8.0"
This will force the use of version 2.8.0 for dropzonejs and dropzonejs_eb_widget, which has proven to be stable and free from the issues associated with version 2.9.0. Make sure to run composer update after making this change to apply the new versions.