Fix HTTP status code in root route and add "Go back" button to error page

backend/server.js

@@ -10,7 +10,7 @@ app.set("view engine", "ejs");
 app.use(express.json({ limit: "10mb" }));
 
 app.get("/", (req, res) => {
-  res.status(502).render("index.ejs");
+  res.status(500).render("index.ejs");
 });
 
 app.listen(port, () => {