Hi Fabien,
I have exactly the same issue, even with 0.91.3. I have tado smart heating control. Can read out all the values, but cannot modify anything through the web interface gauge in home assistant. Same error: 422.
Hope someone can help us.
2019-04-13 19:56:03 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.1869484144] HTTP Error 422:
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/homeassistant/components/websocket_api/commands.py", line 122, in handle_call_service
connection.context(msg))
File "/usr/local/lib/python3.7/site-packages/homeassistant/core.py", line 1138, in async_call
self._execute_service(handler, service_call))
File "/usr/local/lib/python3.7/site-packages/homeassistant/core.py", line 1160, in _execute_service
await handler.func(service_call)
File "/usr/local/lib/python3.7/site-packages/homeassistant/helpers/entity_component.py", line 188, in handle_service
self._platforms.values(), func, call, service_name
File "/usr/local/lib/python3.7/site-packages/homeassistant/helpers/service.py", line 314, in entity_service_call
future.result() # pop exception if have
File "/usr/local/lib/python3.7/site-packages/homeassistant/helpers/service.py", line 330, in _handle_service_platform_call
await func(entity, data)
File "/usr/local/lib/python3.7/site-packages/homeassistant/components/climate/__init__.py", line 564, in async_service_temperature_set
await entity.async_set_temperature(**kwargs)
File "/usr/local/lib/python3.7/concurrent/futures/thread.py", line 57, in run
result = self.fn(*self.args, **self.kwargs)
File "/usr/local/lib/python3.7/site-packages/homeassistant/components/tado/climate.py", line 234, in set_temperature
self._control_heating()
File "/usr/local/lib/python3.7/site-packages/homeassistant/components/tado/climate.py", line 373, in _control_heating
self.zone_id, self._current_operation, self._target_temp)
File "/usr/local/lib/python3.7/site-packages/homeassistant/components/tado/__init__.py", line 122, in set_zone_overlay
self.tado.setZoneOverlay(zone_id, mode, temperature, duration)
File "/config/deps/lib/python3.7/site-packages/PyTado/interface.py", line 278, in setZoneOverlay
data = self._apiCall(cmd, "PUT", post_data, True)
File "/config/deps/lib/python3.7/site-packages/PyTado/interface.py", line 81, in _apiCall
response = self.opener.open(req)
File "/usr/local/lib/python3.7/urllib/request.py", line 531, in open
response = meth(req, response)
File "/usr/local/lib/python3.7/urllib/request.py", line 641, in http_response
'http', request, response, code, msg, hdrs)
File "/usr/local/lib/python3.7/urllib/request.py", line 569, in error
return self._call_chain(*args)
File "/usr/local/lib/python3.7/urllib/request.py", line 503, in _call_chain
result = func(*args)
File "/usr/local/lib/python3.7/urllib/request.py", line 649, in http_error_default
raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 422: