diff --git a/backend/server.js b/backend/server.js
index f46217b..f529b4e 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -45,10 +45,10 @@ async function run() {
     });
 
     function wrapEvent(doc) {
-      if (doc.screenshot_count) {
+      if (doc && doc.screenshot_count) {
         doc.screenshots = [];
         for (let i = 1; i <= doc.screenshot_count ; i++) {
-          minioClient.presignedUrl('GET', minioBucket, `${data.fullDocument.camera}/${data.fullDocument._id}/${i}.jpg`, 60 * 60, (err, presignedUrl) => {
+          minioClient.presignedUrl('GET', minioBucket, `${doc.camera}/${doc._id}/${i}.jpg`, 60 * 60, (err, presignedUrl) => {
             if (err) { return console.log(err) };
             doc.screenshots.push({ url: presignedUrl });
           })