[Bug]: "Unknown error occurred" trying to setup service provider

[Zwo12]

I Have A Problem With:

The integration in general

What's Your Problem

Trying to setup a fresh download of v2.6.0 after using Waste Collection Scheduler for a long time without any problems.

Tried several ways:
Configuration of the integration via YAML (my long time standard), via GUI (commenting configuration lines accordingly), and via GUI selecting the generic source. Neither way leads to a running integration with HA 2025.1.2 (on Proxmox VM). Setup interupts with "Unknown error occured"

I have no icalender installed (as suggested in #2893)
awake 1.0
packaging 24.2
pathspec 0.12.1
pip 24.3.1
pulsemixer 1.5.1
pyparsing 3.1.4
PyYAML 6.0.2
setuptools 70.3.0
yamllint 1.35.1

Source (if relevant)

avl-ludwigsburg.de

Logs

Logger: aiohttp.server
Quelle: /usr/local/lib/python3.13/site-packages/aiohttp/web_protocol.py:451
Erstmals aufgetreten: 15:37:01 (1 Vorkommnisse)
Zuletzt protokolliert: 15:37:01

Error handling request
Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/aiohttp/web_protocol.py", line 480, in _handle_request
    resp = await request_handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/aiohttp/web_app.py", line 569, in _handle
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/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 92, in security_filter_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/forwarded.py", line 83, in forwarded_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/request_context.py", line 26, in request_context_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/ban.py", line 86, in ban_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/auth.py", line 242, in auth_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/headers.py", line 32, in headers_middleware
    response = await handler(request)
               ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/http.py", line 73, in handle
    result = await handler(request, **request.match_info)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/decorators.py", line 81, in with_admin
    return await func(self, request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/config/config_entries.py", line 222, in post
    return await super().post(request, flow_id)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/http/data_validator.py", line 74, in wrapper
    return await method(view, request, data, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/data_entry_flow.py", line 122, in post
    result = await self._flow_mgr.async_configure(flow_id, data)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/data_entry_flow.py", line 341, in async_configure
    result = await self._async_configure(flow_id, user_input)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/data_entry_flow.py", line 388, in _async_configure
    result = await self._async_handle_step(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        flow, cur_step["step_id"], user_input
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/data_entry_flow.py", line 491, in _async_handle_step
    result: _FlowResultT = await getattr(flow, method)(user_input)
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/waste_collection_schedule/config_flow.py", line 409, in async_step_source
    return await self.async_step_args()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/waste_collection_schedule/config_flow.py", line 693, in async_step_args
    schema, module = await self.__get_arg_schema(
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        self._source, self._extra_info_default_params, args_input
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/config/custom_components/waste_collection_schedule/config_flow.py", line 488, in __get_arg_schema
    module = await self.hass.async_add_executor_job(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        importlib.import_module, f"waste_collection_schedule.source.{source}"
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/local/lib/python3.13/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/util/loop.py", line 200, in protected_loop_func
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/config/custom_components/waste_collection_schedule/waste_collection_schedule/source/ics.py", line 15, in <module>
    from waste_collection_schedule.service.ICS import ICS
  File "/config/custom_components/waste_collection_schedule/waste_collection_schedule/service/ICS.py", line 7, in <module>
    from icalevents import icalevents
  File "/usr/local/lib/python3.13/site-packages/icalevents/icalevents.py", line 3, in <module>
    from .icalparser import parse_events, Event
  File "/usr/local/lib/python3.13/site-packages/icalevents/icalparser.py", line 18, in <module>
    from icalendar.windows_to_olson import WINDOWS_TO_OLSON
ModuleNotFoundError: No module named 'icalendar.windows_to_olson'

Relevant Configuration

Checklist Source Error

• Use the example parameters for your source (often available in the documentation) (don't forget to restart Home Assistant after changing the configuration)
• Checked that the website of your service provider is still working
• Tested my attributes on the service provider website (if possible)
• I have tested with the latest version of the integration (master) (for HACS in the 3 dot menu of the integration click on "Redownload" and choose master as version)

Checklist Sensor Error

• Checked in the Home Assistant Calendar tab if the event names match the types names (if types argument is used)

Required

• I have searched past (closed AND opened) issues to see if this bug has already been reported, and it hasn't been.
• I understand that people give their precious time for free, and thus I've done my very best to make this problem as easy as possible to investigate.

[idominiki]

Same problem here

[CoScha]

Same here. I tried it with different sources for Germany, no one works. Other countries still fine.

[idominiki]

First apply this:
#3592 (comment)

Then:
#3512 (comment)

Anything is working again.

[Zwo12]

This worked for me - @idominiki Thank you!