SKAN not receiving postbacks correctly / wrong attribution to "direct"

SKAN / SkAdNetwork Error

1. ERROR: We never received any http request from the "skan.ourdomain.com" as expected.

2. ERROR: All the attributions(YES! ALL OF THE INSTALLS) in the Google Analytics / Singular / AppsFlyer / Twitter / Facebook, shows the source are "direct organic".

We Did These

1. We use Google Ads and Twitter Ads and Facebook Ads to promote our apps. We spent enough money, and got thousands of paid installs from these ads.

2. We set the NSAdvertisingAttributionReportEndpoint to "skan.ourdomain.com".

3. We call the SKAdNetwork.updatePostbackConversionValue(1). in "AppDelegate" and "Subscribe" source codes.

4. And from our app logs, we see there are SKAN_UPDATE_CONVERSION_VALUE_OK.

Source Code

if #available(iOS 15.4, *) {
  SKAdNetwork.updatePostbackConversionValue(1) { err in
    if let err = err {
      Tracker.shared.reportEvent(.SKAN_UPDATE_CONVERSION_VALUE_FAIL, name: err.localizedDescription, value: 1)
    } else {
      Tracker.shared.reportEvent(.SKAN_UPDATE_CONVERSION_VALUE_OK)
    }
  }
} else {
  SKAdNetwork.registerAppForAdNetworkAttribution()
  Tracker.shared.reporxtEvent(
  .SKAN_UPDATE_CONVERSION_VALUE_OLD_VERSION, name: "AppDelegate")
}