Angular/PWA - Site cannot be installed: Page does not work offline

I am currently working on the migration of a web application to a PWA, and since a few days I encounter this problem: "Site cannot be installed: Page does not work offline. Starting in Chrome 93, the installability criteria is changing, and this site will not be installable. See https://goo.gle/improved-pwa-offline-detection for more information."

I did several searches on forums, especially on Stackoverflow to find a solution to my problem, but without success. All the proposed solutions did not solve my problem.

I created this JS script following recommendations found on Stackoverflow :

importScripts('./ngsw-worker.js');

const OFFLINE_VERSION = 1;
const CACHE_NAME = 'offline-html';
const OFFLINE_URL = 'offline.html';

self.addEventListener('install', (event) => {
  event.waitUntil((async () => {
    const cache = await caches.open(CACHE_NAME);
    await cache.add(new Request(OFFLINE_URL, {cache: 'reload'}));
  })());
});

self.addEventListener('fetch', (event) => {
  if (event.request.mode === 'navigate') {
    event.respondWith((async () => {
      try {
        const preloadResponse = await event.preloadResponse;
        if (preloadResponse) {
          return preloadResponse;
        }

        const networkResponse = await fetch(event.request);
        return networkResponse;
      } catch (error) {
        console.log('Fetch failed; returning offline page instead.', error);

        const cache = await caches.open(CACHE_NAME);
        const cachedResponse = await cache.match(OFFLINE_URL);
        return cachedResponse;
      }
    })());
  }
});

This script is executed correctly when the application is run, but the error message persists.

Do you have a solution for this problem?

Thank you.

PS : I use the 8.1.1 version of Angular