I'm trying to find dates for Aadvantage awards in business class. I search correctly but all that shows up is coach--but occasionally, when I go to the award listing page and click on "show calendar" I can see a day here and there with a business award. The problem? 99% of the time the website says "calendar not available". I may have accessed it for a different date/itinerary a few minutes earlier, but then it's no longer available.

I'm on a MacBook Pro and I'm using Safari, then switching to Chrome.

Is there some magic trick to getting to that calendar?

TIA