[BUG] manifest.json file not found by PWABuilder.com

[epikgit]

What happened?

I'm trying to create a PWA and prepared a test environment for that but when I supply the url to PWABuilder.com I got this strange error:
Manifest not found before detection tests timed out
Indeed if I try to download my manifest, it is available.
The test points to a subfolder of a website and so I thought that PWABuilder.com needs the manifest.json on the root of the website.
But even if I put the manifest.json in the root, the problem remains the same.

How do we reproduce the behavior?

1. Go to https://www.pwabuilder.com/
2. Enter this URL in the box https://www.ugmfree.it/ShadesMaster/web.pwa
3. Check the error

If you want to check the existance of the manifest.json file, enter this URL in your browser: https://www.ugmfree.it/ShadesMaster/web.pwa/manifest.json

What do you expect to happen?

Well I expect the PWABuilder.com find my manifest.json file.

What environment were you using?

The web server is IIS 7 so the configuration is on a web.config file.
The browsers I tested, even if this is a server side problem, are FF, Edge, Chrome, all of them on their latest version.

Additional context

No response

[microsoft-github-policy-service]

This issue has been marked as "needs attention 👋" since it has not been triaged for 7 days. Please triage the issue .

[microsoft-github-policy-service]

This issue has been marked as "needs attention 👋" since it has not been triaged for 7 days. Please triage the issue .

[microsoft-github-policy-service]

This issue has been marked as "needs attention 👋" since it has not been triaged for 7 days. Please triage the issue .