Web push notification not showing

I registered a service worker and am trying to test a web notification in the browser. Chrome (and Firefox) claim the service worker is successfully registered.

On load of the React App, I've granted permission to receive notifications.

In my sw.js, I am listening for a push event, and attempting to send a sample push message from the Chrome Application tab, as shown in the screenshot above.

self.addEventListener("push", receivePushNotification);

When clicking Push in the Chrome Application Tab, the push event fires, calling receivePushNotification. However, when I attempt to show a notification in the browser, nothing happens and no error is reported.

function receivePushNotification(event) {
  // This prints "Test push message from DevTools."
  console.log("[Service Worker] Push Received.", event.data.text());

  var options = {
    body: "This notification was generated from a push!"
  };

/*****
  I would expect the following line to display a notification, since I've already 
  granted permission to allow for notifications. Yet, nothing happens and there is 
  no error in the console.
*****/

  event.waitUntil(self.registration.showNotification("Hello world!", options));
}

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