Riemann sum not working

Hello there,
so I have a Sonoff Pow R2 that I use for monitoring consumption of my PC, with this sensor:

sensor:
 - platform: template
   sensors:
     computer_power:
       friendly_name: computer_power
       #unit_of_measurement: W
       value_template: "{{ state_attr('switch.10004c6e11', 'power') }}"

Now… this is an instant consumption, so I need the Riemann Sum to get the consumption per hour, in kWh:

 - platform: integration
   source: sensor.computer_power
   name: computer_consumo
   unit_prefix: k
   unit_time: h
   round: 2
   method: left

The template sensor is working, not it showing 149,8, but the Riemann Sum sensor keep saying UNAVAILABLE and I can’t understand why…
Can you please help me?
Thanks in advance

PS: As you can see I’ve tried commenting the unit of measure for my template sensor, but nothing has changed

You need the unit of measurement in the template sensor. Uncomment that.

Remove these two lines from the Riemann sensor and see what happens:

   unit_prefix: k
   unit_time: h