I'm having this strange problem in my wordpress installation on a server that uses Nginx:
When I upload an image through the media library, everything seems to go fine (file is saved, miniatures are created, ...) except that when I try to show the original uploaded image it returns a 403 (forbidden) error. Permissions and user for both containg folder and the file itself are correct, and, in fact, all miniatures created by wordpress (in the same folder) are displayed correctly, so i.e. /wp-content/uploads/2016/08/image1.jpg shows the error but /wp-content/uploads/2016/08/image1-200x200.jpg shows the image.
I tried disabling Nginx and using Apache and then all works fine and the original uploaded images are served without error... but I really would like to make it work with Nginx. Any ideas?