Can't set up OK Google voice detection

[MxtrMeike13]

I've been trying to set up my Google app on my Samsung Galaxy S6. I open the app, go to settings, and click on Voice. But then, when I select "Ok Google" detection, it opens for less than a second before that section collapses back into the Voice section. If I'm fast enough to click on the setup button, it takes me to the setup screen...but even when I click "Next", nothing happens. How do I fix this??