Progress Indicator Not Showing

Here's the content of my app.js file:

import { createApp, h } from 'vue'
import { createInertiaApp } from '@inertiajs/vue3'

import NProgress from 'nprogress'
import { router } from '@inertiajs/vue3'

createInertiaApp({
  resolve: name => {
    const pages = import.meta.glob('./Pages/**/*.vue', { eager: true })
    return pages[`./Pages/${name}.vue`]
  },
  setup({ el, App, props, plugin }) {
    createApp({ render: () => h(App, props) })
      .use(plugin)
      .mount(el)
  },
})

let timeout = null

router.on('start', () => {
  timeout = setTimeout(() => NProgress.start(), 250)
})

router.on('progress', (event) => {
  if (NProgress.isStarted() && event.detail.progress.percentage) {
    NProgress.set((event.detail.progress.percentage / 100) * 0.9)
  }
})

router.on('finish', (event) => {
  clearTimeout(timeout)
  if (!NProgress.isStarted()) {
    return
  } else if (event.detail.visit.completed) {
    NProgress.done()
  } else if (event.detail.visit.interrupted) {
    NProgress.set(0)
  } else if (event.detail.visit.cancelled) {
    NProgress.done()
    NProgress.remove()
  }
})

Simulating delay when navigating:

 public function template()
    {
        sleep(5);
        return Inertia::render('Template');
    }

I can't figure out why progress indicator is not showing. Any ideas on what is missing?