it does't work "Access with Voice Match" in Lg G6

[Android Central Question]

I tried to access "Voice Match" many times. It is enter the page that say "OK Google" 4 times and I'm done all step! Then I click previous botton. But I can see it doesn't check. (It is still grey line, not blue) What can I do to solve this problem? I was tried to all solutions in this site and googling. Plz help me.