Siri activates when you press the side or Home button, but doesn't activate when you say "Hey Siri
Siri activates when you press the side or Home button, but doesn't activate when you say "Hey Siri
iPhone XS Max, iOS 16
"Hey Siri" needs to be enabled in settings. Go to Settings > Siri & Search and make sure both the "Listen for Hey Siri" and "Allow Siri when Locked" switches are on.
If it still doesn't work check out this Apple support note: If "Hey Siri" isn't working on your iPhone - Apple Support