Maven beacon button auto Greyed out?

So I've played all thru T16 in 3.13 and just beat 1 socket 4 conquerors. But I have never been able to get maven to any of my fights. So why is this and why is her button always greyed out? Is there a controller button that I have to hit to enable it?

It says at the bottom of the screen when you are at the map device: L3 + up.