@Victor mystery solved! Wooo!
@Daniel_Atanasovski The gen 2 Garmin sensors are bulletproof. The most common issue with them is a tired battery. Please make sure you have a fresh CR2032 battery.
A common setup mistake is pairing the sensor directly to iOS in the way you pair Bluetooth earbuds. Please check if it’s one of the stored Bluetooth devices in iOS Settings > Bluetooth, and “forget” it by long-pressing the “i” symbol.
Lastly, if you have the Garmin Connect app on your phone and/or a bike computer on your handlebars, it might steal the Bluetooth signal before the Zwift app launches. You may have to remove the Garmin Connect app to prevent this from happening per Garmin’s support site.