Timed out waiting for fetched start_url

That start_url isn't right it should start with a /

Please be sure to delete your existing service worker.

When I look at the URL, it appears that slashes inside manifest.json are being escaped when they don't need to be:

{
  "name": "S1BIOSE",
  "short_name": "S1BIOSE",
  "display": "standalone",
  "background_color": "#ffffff",
  "theme_color": "#8aba12",
  "description": "Vivre sain - Vivre bien",
  "lang": "en",
  "icons": [
  {
    "src": "s1biose.com\/sites\/default\/files\/pwa\/logo-petit-512x512_1.png",
    "sizes": "512x512",
    "type": "image\/png"
  },
  {
    "src": "s1biose.com\/sites\/default\/files\/pwa\/logo-petit-512x512_1.pngcopy.png",
    "sizes": "192x192",
    "type": "image\/png"
  },
  {
    "src": "s1biose.com\/sites\/default\/files\/pwa\/logo-petit-512x512_1.pngcopy2.png",
    "sizes": "144x144",
    "type": "image\/png"
  }],
  "start_url": "\/",
  "scope": "\/"
}

I wasn't recommending an immediate solution, but wanted to point out that the manifest.json seems to be outputting malformed values for start_url and the URIs for icons.

When I read the docs for json_encode I see in the $options the possibility of setting JSON_UNESCAPED_SLASHES. I believe this would fix the problem.

Can you try this patch and see what happens?

Sorry, I read the docs wrong and the array() was unnecessary. New patch in this comment.

Buddy you gotta read how issue statuses work please.

@zenimagine you're right, this module has been tested on very few production websites. We just released the first beta a few days ago, which seems to be what brought you here. It's not a stable module yet, so it puzzles me you have such high expectations.

We appreciate all testing and feedback, but (as with the rest of Drupal) it comes with the standard disclaimer that you're using free, open source software with absolutely no warranty. If you want every problem fixed immediately, you can speed the process by providing patches, or you can hire either myself or another maintainer for contract work.

The escapes for slashes bug me. That's not coming from the pwa module, but from other code that outputs JSON. You have schema_metatag module in play per https://www.drupal.org/project/pwa/issues/3070050 which, if I recall correctly, escapes slashes in its output JSON-LD. Reviewing that now, but if you could please disable schema_metatag and report back whether the problem with your manifest persists.
My hunch is that various modules are overly global or generic while hooking into the JSON filtering and output process, including perhaps us here.

That said, rupl is right, you need to realize that this module is in heavy development at the moment, and also that this project is run by volunteers who may or may not get paid by a company to maintain community projects. If our company were to bill for our time put into here the invoice would be fairly substantial already.

In the meantime thank you for the time you have put in testing, and reporting and documenting issues.

oh what? if this isn't being tested on a clean install it's not even a bug report yet. this is support, plain and simple.

@zenimagine please install the D8 PWA module on a clean install of D8 and see if the problem persists. Until then this is a support request and we can safely de-prioritize. Please do not reclassify the Priority or Status until you have reproduced on a fresh D8 install that includes no other modules.

Try this patch on the latest dev.

So one question: you have configured the SW to cache your start URL, correct? Overall I'm wishing you would provide more information we could use to provide support. Simply telling us that it didn't fix your support request gives people very few options in terms of next steps.

Visiting your site now I see start_url is loading and no errors.

Ok so I am implementing this on a site now with a similar redirect to you and got the same error, the reason this is showing is that you are using / as the start URL and it should be /fr (in your case), or wherever your page is redirecting to. When Chrome is doing the Lighthouse testing this is registering as a redirect.