Fast forward to February 2025 - has this ever been resolved? It is still happening. All I can do is follow the instructions that were given to us…
Update April 2025. Not working now and hasn’t been working for years for me. Same callback error. Theres some info at The Withings Callback URL does not work · Issue #86353 · home-assistant/core · GitHub
But the tutorial just links to nabu casa, presumably thats where to set up.