@AussieNSW You are not doing anything wrong!
I had the same issue. I was online from 7.40am and could see everything and the 'early access available' notification, but no matter what I tried, I got the error message - nothing available for your party on ALL AUNZ cruises. I ended up calling, and the guy had many issues as well! My phone call was about 50mins in total because the poor guy kept having to put me on hold to speak to IT/Superiors. But we got there in the end.
Then as soon as I got off the phone call, online started working. It was also just after 9am, so wondering if they set the online time to 9am not 8am?