Enable automatic sign-in across apps and websites in android

Question

This is the doc I am trying to support from my app.

Enable automatic sign-in across apps and websites

To support this feature, I've followed all procedures that described here.

This is my https://my.website.com/.well-known/assetlinks.json

[
    {
        "relation": [
            "delegate_permission/common.get_login_creds"
        ],
        "target": {
            "namespace": "web",
            "site": "https://my.website.com"
        }
    },
    {
        "relation": [
            "delegate_permission/common.get_login_creds"
        ],
        "target": {
            "namespace": "android_app",
            "package_name": "com.my.app",
            "sha256_cert_fingerprints": [
                "XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX"
            ]
        }
    }
]

However, I don't see any credential associations in app.

1. My app that has the asset statement has been published in beta channel. Yes, the app has been signed with the same prod key from Google Play Store (not dev or test key)

   (According to Google survery, alpha/beta channel should be working fine)

2. According to the doc, Google survey is optional, but I've submitted two times. However, still no response yet(more than 2 days now).

3. My web site is publicly accessible and doesn't have any robots.txt.

4. Yes, that assetlinks.json returns 200 and application/json content-type.

I am not sure what else I should try more to see this credential associations happening in the app.