Due to privacy configurations implemented by Apple for Safari, an additional setting change is required for those using Safari on both iOS and desktop devices. 

On an iPhone or iPad 

1. Open Settings
2. Scroll down and tap on Safari
3. Scroll to the Privacy & Security section and turn off “Prevent cross-site tracking” 

On a Mac 

1. In the Safari app on your Mac, choose Safari > Preferences, then select thePrivacy tab 
2. Deselect “Prevent cross-site tracking”

 

When the App Manager and Headless URLs have different top-level domains, cross-domain communication is subject to Intelligent Tracking Protection (ITP). ITP is a privacy protection in many browsers to block requests for cross-website tracking including third-party cookies blocked, cookies blocked, or when a user has multiple AD accounts.

For this reason, it is a pre-requisite to have the Headless site and App Manager URL be on the same top-level domain, to prevent such issues with Safari and other browsers.