title: Firebase Analytics UTM campaign tracking not working with iOS
body: <p>I am using React Native to build an app. I track events and other metrics with Firebase.</p>
  
  <p>I would like to launch a custom campaign (newsletters, newspaper ads, etc.)
  I am trying to track app installs (first_open) on iOS and Android and I am still unable to track iOS installs.
  I tried with <a href="https://developers.google.com/analytics/devguides/collection/ios/v3/campaigns" rel="nofollow noreferrer">https://developers.google.com/analytics/devguides/collection/ios/v3/campaigns</a> but the url generated is not working and for me it is weird that this form require Google Analytics Property ID.</p>
  
  <p>Anyone know how to build this kind of URL?</p>