Why does ok google not open on my samsung s9?

[Android Central Question]

I just updated my s9 software this afternoon, and ever since ok Google will not open my phone and respond. When I say it and then hit the power button when it doesnt do anythinh, the only thing it does is have Google assistant open - it doesn't turn on my screen and respond automatically anymore. I.e I used to say 'ok Google play music' when I couldn't find my phone before, and it would immediately play music. The settings are all the same as before - smart lock unlock phone with ok Google and the correct options ticked.