I haven't run into that issue yet. What I do when I get to the homepage using a VPN is click on the globe icon at the top of the page, then I enter in TYO for the city field and click English. But it sounds like you're automatically redirected to that "acknowledge" page? Are you going to "https://www.ana.co.jp/" instead of "https://www.ana.co.jp/en/us/"? Not sure if that changes anything. If not then maybe it's your VPN?