Drupal - Private files not found 404 error
Ok, I got this issue fixed.
The Vanish installed on server was causing the issue more specifically the following code.
# Always cache the following file types for all users.
if (req.url ~ "(?i)\.(pdf|woff|eot|svg|ttf|png|gif|jpeg|ico|swf|css|js|html|htm)(\?[a-z0-9]+)?$") {
unset req.http.Cookie;
# Stop processing further for those file types. This way, we ensure to have
# X-Varnish-Cache HIT for those requests.
return (lookup);
}
You can either remove the file extensions from above code or comment the entire block. This should solve the issue.