Setting up “Hey Siri”

There’s a pressing issue I’m currently experiencing with my iPhone 7plus. I can’t set up the ‘Listen to Hey Siri’ feature. At first I thought it was an issue with my microphone but Siri hears me and works fine when I activate it with my home button. But when I try to enable the ‘listen for Hey Siri’, it goes on to the part where I’m supposed to say “hey Siri” and I do it just gets stuck for a while and tells me “Siri didn’t quite get that. Try again.” I’ve attached screenshots.