HomeAssistent can read Melcloud data, can't send commands

We have and Mitsubitshi Ecodan heat pump.

Intalled the integration, and we are able to read the data provided by Melcloud. The other direction, sending commands with automation does nothing (like a simple on off or HVAC from cool to heat).

Is somewhing extra needed next to installing the integration to get it working?

A simple automation for testing, manualy activating:

alias: TEST - Warmtepomp Koelen
description: ""
trigger: []
condition: []
action:
  - device_id: 7733e42b9c6654ae6ecec2ea84b1ab51
    domain: climate
    entity_id: climate.warmtepomp_zone_1
    type: set_hvac_mode
    hvac_mode: cool
mode: single

Thanks in advance!