Unable to fetch a list of attachment IDs to process from the WordPress REST API.

Hi, recently i have installed this plugin , and when tryed to regenerate thumbnails i get this error:

Unable to fetch a list of attachment IDs to process from the WordPress REST API. You can check your browser's console for details.

I checked on google, and found this URL as test:

https://siteurl.com//wp-json/wp/v2/media?page=1&per_page=25&_fields=id&is_regeneratable=1&exclude_site_icons=1&orderby=id&order=asc

but get 404 Forbidden when tryed that. Some server limitation maybe? Help?

The page I need help with: [log in to see the link]