explicitly listen to all IPv4 interfaces

index.js

@@ -23,6 +23,6 @@ app.post("/api/fileanalyse", upload.single("upfile"), (req, res) => {
   });
 });
 
-app.listen(PORT, function () {
-  console.log("Your app is listening on port " + PORT);
+app.listen(PORT, "0.0.0.0", function () {
+  console.log('Your app is listening on interface "0.0.0.0" and port ' + PORT);
 });