As I wrote in my first post, i can upload files properly, so i think the settings (keys) should be fine. You can check it out on the screenshot below :
It is most likely that when you set the Key-value to “Parents Group’s Chapitre’s Video’s URL” and trigger the delete action, the removal of the “Video File’s URL” does not happen.
Allow me to suggest you change the Key-value to something else (keeping the relation to the file you want to delete) - set the Key value requesting to the table where your video file URL is placed (Input where your file is placed).
Or you may set the Delete file workflow as it is shown on the plugin demo page - this option will work for sure.
After the workflow has run, the indicated files will be deleted from the S3 Bucket.
Please try to change it exactly as on my screenshots and let me know if all is working now.
In case if you still will encounter your issue, please share with us the screenshots of your workflow and current settings of the plugin elements and we will investigate your use case.