Why is "Hey Siri" not working on iPhone 16 Pro?

Suddenly “Hey Siri/Siri” no longer works on my iPhone 16 pro!! I’ve had my iPhone for 4 months. It worked fine until tonight. I checked to make sure the text to Siri wasn’t selected, but that’s not even an option. I didn’t change anything. I Did restart my phone this morning.

[Re-Titled by Moderator]