Link does not open file (image) correctly

Hello;

I have used this plugin for several years to have my clients attach a photo with proof of payment to their order.

But today, when I click on the link to open the file I can’t see the image and instead only strange characters appear in plain text. This happens both from the confirmation email and from the order.

Please check: https://importacionesarturia.com/wp-admin/post.php?post=132121&action=edit&_wpnonce=497328ac92&wpw_cfu_download_file_uploader=1&wpw_cfu_download_file_key=0&wpw_cfu_download_file_order_id=132121

But when from the order, when I click on the download icon the file I can see this without problems.

Could you please help me?

Thank you

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