diff --git a/1-Authentication/1-sign-in/App/package.json b/1-Authentication/1-sign-in/App/package.json
index 8eeddf1..35fe875 100644
--- a/1-Authentication/1-sign-in/App/package.json
+++ b/1-Authentication/1-sign-in/App/package.json
@@ -7,7 +7,7 @@
     "start": "node server.js",
     "dev": "nodemon server.js",
     "test": "jest --forceExit",
-    "postinstall": "cd ../../../Common/msal-node-wrapper && npm install"
+    "postinstall": "cd ../../../Common/msal-node-wrapper && npm install && npm run build"
   },
   "author": "derisen",
   "license": "MIT",