Thank you, no problem. I apologize for posting this in the wrong section of the forum. I hope people can share their opinions and help me out now.

P.S. I don't see any issues or concerns regarding the inability to view your bookings with American Airlines on any online platform. If this were a widespread problem, it would certainly impact people's ability to fly with them, especially since it has been ongoing for over a month. I have a feeling that American Airlines might be creating the impression that I'm unable to log into my booking in order to encourage me to enroll in the Advantage membership.

I called American Airlines in Australia, and they kept saying, "It's on our end," and expressed their apologies for my inability to view my domestic flight booking. They mentioned that there are some issues with the AA website. Then, two weeks later, I called the U.S. number, but they didn’t provide a clear reason for the problem. Instead, they jumped to the conclusion that I should sign up for the American Airlines Advantage program. They insisted that once I sign up, I will be able to view my domestic booking and access other features.

I don't understand why I need to sign up just to see a single flight. It seems as if AA has logged me out of my flight details. Perhaps this is related to the changes I made with United Airlines; however, the only adjustments I made were to change my departure dates and the time for the United Airline which is the Las Vegas to LAX only. I didn't make any changes to my American Airlines itinerary. But yes 2 times again with American airline and just 1 with Qantas but no American airline changes. And still kept the package as a whole. Just changes to the 1 day stay in LA and the time frame but nothing else. The getting there to USA and the return to Australia stays the same with no changes. Only some minor changes within the trip itself usually for the domestic flights

In the future, I will take this as a learning experience. Next time instead package i will just do getting to USA and return as a package and the domestic flights in America will be separate tickets. Instead of a whole package. There for i have more power for each individual company airline the AA and United and Qantas instead of only Qantas controls everything.