At chapter VI, I'm trying to get Miraak's dragon to bend to my dragon shout "Bend will". I have unlocked all 3 words for it, directed the shout at him but he does'nt respond and before I know it, can't fight & I've failed, then returned to Solstheim. I've tried it 3 times and same result, My magicka, health and stamina are on max at lvl 37, what am I doing wrong? this is frustrating!

Are you sure you have all three words unlocked? Triple check.

If you do, reload a save before you enter the loading screen that leads you to Sahrotaar.