I can get to landing page for the official site and can even get to "Opening Times and Tickets" page: https://colosseo.it/en/opening-times-and-tickets/.
However, the minute I select buy tickets I get a Blocked Page Octofence: "You have received a 403 error message while trying to access this website. This is because the website owner has chosen to block your IP address or country from accessing this website."
Is this because they go offline after their hours? It was about 430-5p Rome time when I was browsing. Or is this message something else?