Login error Toon thermostat

[Afterburner]

I got a Toon thermostat from friends, arranged a login account on My Eneco and tried to connect to my Toon environment with the Toon module in Domoticz. The Toon thermostat itself works fine and is connected to the Internet. My Eneco is also working as well as the Toon app on my mobile.
I added Toon in the Hardware section with the credentials from My Eneco, but, no devices appear. The log mentions every 5 minutes: ToonThermostat: Error login! What happens here? Can anyone help. Is the Toon module still functional and using the right API procedures?

Domoticz data: Version: 2020.2
Build Hash: b63341bc0
Compile Date: 2020-04-26 13:47:55
dzVents Version: 3.0.2
Python Version: 3.8.5 (default, Jul 28 2020, 12:59:40) [GCC 9.3.0]