Automation: climate turning on triggered by current_temperature

hello everyone
first topic here and first configuring on home assistant. So please forgive me if I’m asking somthing too basic

I’m trying to setting my (first) automation on these A/C controllers: I’m trying to set (for now) a simple turn_on triggered by a current_temperature attribute below some value.
Here it is

trigger:
platform: numeric_state
entity_id: climate.camera_da_letto
value_template: ‘{{ state.attributes.current_temperature }}’
below: 20
action:
service: climate.turn_on
entity_id: climate.camera_da_letto

Thing is, it does nothing and I have no error in the log
any help or suggestion?

thank you

Giuseppe