diff --git a/mod/nginx/bbb/greenlight.nginx b/mod/nginx/bbb/greenlight.nginx
index 8ed654b..4ed4626 100644
--- a/mod/nginx/bbb/greenlight.nginx
+++ b/mod/nginx/bbb/greenlight.nginx
@@ -26,4 +26,9 @@ location /b/cable {
   proxy_send_timeout  6h;
   client_body_timeout 6h;
   send_timeout        6h;
-}
\ No newline at end of file
+}
+
+# this is necessary for the preupload_presentation feature
+location /rails/active_storage {
+  return 301 /b$request_uri;
+}