App missing in the iPhone 14 - iOS 16.4.1 Notification Settings

Hi there, there's an app that I've been testing for the push notifications from TestFlight. I can't find it in the Notification Settings of my iPhone 14 - iOS 16.14.1 version. I already uninstalled the app and reinstalled. I did reset all settings of my iPhone but the issue still persists. There's also no prompt to allow notification when opening the app. Anyone can help this? Is this the app's problem or issue from the Apple's side? Thank you.