I have developed an e-commerce site using Angular 9. There are some third-party web applications that make use of my application. For the purpose of this question, these look like the following:

• App1(My application URL): www.my-ecommerce.com
• App2(1st third-party) : www.thirdparty1.com
• App3(2nd third-party) : www.thirdparty2.com

App2 and App3 have some buttons. Upon clicking those buttons, App1 will pop-up in an iframe.

I am trying to add Google Analytics to App1. Google Analytics is not getting any data in this case. When I directly access App1, analytics works, but when accessing through other websites, it is not working.

Why not?