New warning "Site cannot be installed: Page does not work offline. Starting in Chrome 93..." after Chrome update in Angular 10 PWA

Question

Angular 10.2.4 Progressive Web App is served on Apache Tomcat 9.0.41 over HTTPS and can work offline. After an update to Google Chrome Version 89.0.4389.72 (64-Bit) we get a warning in DevTools on first load:

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.

Also in the network tab, I see two failing fetches:

Name	Path	Url	Status	Type	Initiator
example.com	/	https://example.com	(failed) net:ERR_INTERNET_DISCONNECTED	fetch	ngsw-worker.js:2795
ngsw.json?ngsw-cace-bust=0.8890368493450784	/ngsw.json	https://example.com/ngsw.json?ngsw-cache-bust=0.8890368493450784	(failed)	fetch	ngsw-worker.js:2795

The PWA can still be installed without problems.

This warning is also shown when a new Angular project is created from scratch (for Angular version 10.2.4):

ng new
ng add @angular/pwa

Any ideas on what causes this warning and the failing network fetches...?

Answer 1

Changing 'start_url' in 'manifest.webmanifest' to '/index.html' was the solution for me (see issue on Github):

"start_url": "/index.html",

The warning in DevTools does not appear any more and I am still able to install the PWA. I will use this solution as a workaround until there is an official fix.

Update (17/04/2021): Google just updated the blog post and withdrawed the change. The warning will be removed around Google Chrome v90. So we can undo the changes on the service worker (since the Angular service worker already works offline).