Subscription not Connecting when changing to new library

We have a subscription working with the previous libraries - I started a new project using only the following page:

I’ve used both firefox and chrome.

The subscription does not connect. My troubleshooting:

  1. Checked connection on studio, set to subscriptions-transport-ws
  2. Checks:

$ node index.js
Server is now running on localhost:4040/graphql

$ npx diagnose-endpoint@1.1.0 --endpoint=ws://localhost:4040/graphql
Diagnosing ws://localhost:4040/graphql
Failed to diagnose any problems with the endpoint. Please email with the endpoint to help us investigate🙏