New user and tado is not working

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I just moved in a house with a fully installed tado system. The owner did not want to invite me because he was a legacy user and he was afraid of loosing his perks.
But now I have everything in my account.
The thermostat, the bridge and all 12 smart thermostat valves.
All seems communicating, however there seem not be any heat request going to the Heating system.
I tried to do a reinstall of the thermostat but I'm stuck as I don't know what thermostat was used before.