diff --git a/src/serve_rendered.js b/src/serve_rendered.js
index e4742a6..bbb76ac 100644
--- a/src/serve_rendered.js
+++ b/src/serve_rendered.js
@@ -424,7 +424,7 @@ module.exports = (options, repo, params, id, publicUrl, dataResolver) => {
         pool.release(renderer);
         if (err) {
           console.error(err);
-          return;
+          return res.status(500).send(err);
         }
 
         // Fix semi-transparent outlines on raw, premultiplied input