I’m trying to get Home Connect working to connect a new dishwasher. I have started the integration installation, worked my way through the prompts (included avoiding the authorisation error that all posts online seem to refer to), clicked the box to agree to HA accessing my Home Connect details, then I click the “Link Account” button which is a local HA URL. At that point I am redirected back to the “Integrations” page of my HA instance but greeted with a box which simply says ‘Error’. There are no other details.
The Home Connect credentials are visible in the “Application Credentials” screen of HA, so there’s definitely something happening. The HA Core log contains the following, which I guess suggests something is wrong with the contents of an oauth call somewhere, but I neither understand nor can fix it. My Home Connect username (and my developer username) don’t contain any uppercase characters (as noted in the documentation). Any suggestions gratefully received! I don’t need my dishwasher connected to HA, but it’s bugging me that it doesn’t work. 
Logger: aiohttp.server
Source: helpers/config_entry_oauth2_flow.py:209
First occurred: 8 March 2023 at 21:39:11 (4 occurrences)
Last logged: 07:24:11
Error handling request
Traceback (most recent call last):
File "/usr/local/lib/python3.10/site-packages/aiohttp/web_protocol.py", line 433, in _handle_request
resp = await request_handler(request)
File "/usr/local/lib/python3.10/site-packages/aiohttp/web_app.py", line 504, in _handle
resp = await handler(request)
File "/usr/local/lib/python3.10/site-packages/aiohttp/web_middlewares.py", line 117, in impl
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/security_filter.py", line 67, in security_filter_middleware
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/forwarded.py", line 100, in forwarded_middleware
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/request_context.py", line 28, in request_context_middleware
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/ban.py", line 80, in ban_middleware
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/auth.py", line 235, in auth_middleware
return await handler(request)
File "/usr/src/homeassistant/homeassistant/components/http/view.py", line 146, in handle
result = await result
File "/usr/src/homeassistant/homeassistant/components/config/config_entries.py", line 171, in get
return await super().get(request, flow_id)
File "/usr/src/homeassistant/homeassistant/helpers/data_entry_flow.py", line 96, in get
result = await self._flow_mgr.async_configure(flow_id)
File "/usr/src/homeassistant/homeassistant/data_entry_flow.py", line 271, in async_configure
result = await self._async_handle_step(
File "/usr/src/homeassistant/homeassistant/data_entry_flow.py", line 367, in _async_handle_step
result: FlowResult = await getattr(flow, method)(user_input)
File "/usr/src/homeassistant/homeassistant/helpers/config_entry_oauth2_flow.py", line 315, in async_step_creation
token = await self.flow_impl.async_resolve_external_data(
File "/usr/src/homeassistant/homeassistant/helpers/config_entry_oauth2_flow.py", line 172, in async_resolve_external_data
return await self._token_request(
File "/usr/src/homeassistant/homeassistant/helpers/config_entry_oauth2_flow.py", line 209, in _token_request
resp.raise_for_status()
File "/usr/local/lib/python3.10/site-packages/aiohttp/client_reqrep.py", line 1005, in raise_for_status
raise ClientResponseError(
aiohttp.client_exceptions.ClientResponseError: 400, message='Bad Request', url=URL('https://api.home-connect.com/security/oauth/token')
