Fritz!Dect not working with generic thermostat

I have created a gerneric thermostat. The real thermostat is an AVM Fritz!Dect 301. The temperature sensor is a DIY Tasmota sensor, which also works perfectly as a device in HA. The actual temperature from the sensor is displayed in the generic thermostat. However, the real thermostat does not take over any settings from the generic one. I can neither regulate the temperature nor switch the heating on or off. The configuration of the gerneric thermostat looks like this:

  - platform: generic_thermostat
    name: Heizung Hedi
    unique_id: thermhedi
    heater: climate.hedi01
    target_sensor: sensor.tasmota_am2301_temperature
    min_temp: 8
    max_temp: 26
    ac_mode: false
    precision: 0.5
    target_temp_step: 0.5
    comfort_temp: 21
    away_temp: 16
    sleep_temp: 16
    precision: 0.1

The ids of the target_sensor and the heater are absolutely correct.

Has anyone already had experience with this combination and perhaps got it to work?