Why would a guy cancel a hookup?

Why would a guy cancel a hookup if he was single before n after? I've known him for a while. Talk online only because we mostly live far apart. Last year he was on holiday where I live and we arranged to meet and hookup, but 2 days before he cancelled. Why? I stopped talking to him but he got into contact again and talks like normal friends no hookup kind of talk yet.
Why would a guy cancel a hookup?
Post Opinion