Yasuo's Ultimate

I am a main and there has been many times that I try to ult off of my knock up or a team mates knock up, but there has been many times where my ultimate wouldn't activate. I know for a fact that I am within range of my ultimate, but when an enemy champion is knocked up the ability wont light up as available. I was just wondering if anyone else in the league community that uses Yasuo is having this problem.