[APP][Pro] MELCloud & MELCloud Extension - Take control of your heat pump

@Marius_Stensrod, this post for the Home Assistant integration from today confirms the global issue: Error setting up entry AC's MELCloud for melcloud · Issue #103973 · home-assistant/core · GitHub

You can try to go to your device settings > maintenance, and reauthenticate so a new token will be generated (but without warranty it will fix the issue).