Heart rate monitor pairing

Hi all
I’m a newbie to zwift. I’m can’t seem to pair my hrm at the start of the ride. It’s a Garmin hrm tri.
The app connect to the turbo fine but when I tap heart monitor it can’t find it.
The hrm will connect fine to my watch. I’ve turned the watch off, left the watch in the house and tried again. Even reloaded the app but still can’t find the hrm. The only thing I’ve not done is change the battery but as said previously it work when connected to the watch.

Any help would be appreciated

Thanks
Darren

What are you trying to pair it to? Apple TV or iPad or sth like that?
Maybe the Garmin HRM only supports ANT+ while the Apple supports only Bluetooth?