
How can I be sure that the .ac domain is safe???
It is a strange situation. As far as I know, Betfury has never had a .ac domain before. It looks very suspicious, considering that Betfury has not had any warnings about the .ac domain, and it is not on the official Mirrors page. Maybe I am mistaken, but redirecting to this domain on your screenshot looks too much like phishing.
I would also be careful with the .ac domain; I just tried to visit the site and you get automatically redirected to the .ai domain and also in there list of official mirrors there is no link of the .ac domain name. One option could be to just ask about it in livechat or telegram to know for sure what the official mirror sites are for Betfury.