Thanks @Xavier82. The restart after 5 minute option did not solve my issue. Thats why I renewed the key.
Still the question how to normalize the data. Enyone?

3 days ago the Envoy stopped publishing data to Domoticz. In log indeed the above mentioned Invalid data received! (no session_id) message. After logging in manualy to Envoy I was asked to generate a code. According to the Domoticz wiki I entered this code in de Domoticz user variable and after some ...