Trying to receive Installation-validation postback using SKAdNetwork

Hi,

I am using App Store Connect Campaign Links on my campaigns, like email campaign, Facebook and Instagram campaigns.

I would like to know which campaign is going good.

For that, i have done the below two steps to track app installation and campaign details, like Source of installation.

Set NSAdvertisingAttributionReportEndpoint in info.plist

SKAdNetwork.updatePostbackConversionValue(0) in didFinishLaunching

Also, enabled the server endoint https://<MyDomain.com>/.well-known/skadnetwork/report-attribution/ to accept HTTP POST messages.

Now, i am trying to test the postback from TestFlight build of my app.

But i am getting the below error in console.

Error setting developer pingback domain for app: <MY_APP_ID>, error: (null), result: 0

Am i doing anything wrong? Please advise,

Thank you.