problem with volume

HI all…
I ve created the pawn and a volume so this monster can chase me…now why this monster can’ go on this stairs? He get go on the second stairs but she can down the stairs …why?

There is a setting for max step size and max angle for pawns.

nono i arleadt see… i controll all the variable of the monster with that of my character…and they are the same but my character can go there…the monster stop to the seconds stair

Please help me i need xD