Internal error: 'NoneType' object is not iterable

In the Traceback field theres the following:

 File "/omd/sites/monitor/lib/python3/cmk/gui/wsgi/applications/checkmk.py", line 166, in _process_request
    response = page_handler()
  File "/omd/sites/monitor/lib/python3/cmk/gui/wsgi/applications/utils.py", line 59, in _call_auth
    func()
  File "/omd/sites/monitor/lib/python3/cmk/gui/pages.py", line 182, in <lambda>
    return (lambda hc: lambda: hc().handle_page())(handle_class)
  File "/omd/sites/monitor/lib/python3/cmk/gui/pages.py", line 46, in handle_page
    self.page()
  File "/omd/sites/monitor/lib/python3/cmk/gui/pages.py", line 154, in <lambda>
    "page": lambda self: self._wrapped_callable[0]()
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 1791, in page_view
    process_view(GUIViewRenderer(view, show_buttons=True))
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 1829, in process_view
    _process_regular_view(view_renderer)
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 1846, in _process_regular_view
    _show_view(view_renderer, unfiltered_amount_of_rows, rows)
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 2023, in _show_view
    view_renderer.render(rows, show_checkboxes, num_columns, show_filters,
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 611, in render
    page_menu=self._page_menu(rows, show_filters))
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 791, in _page_menu
    self._page_menu_dropdowns_context(rows) + \
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 857, in _page_menu_dropdowns_context
    return _get_context_page_menu_dropdowns(self.view, rows, mobile=False)
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 2393, in _get_context_page_menu_dropdowns
    topics=host_setup_topic + list(
  File "/omd/sites/monitor/lib/python3/cmk/gui/views.py", line 2525, in _get_context_page_menu_topics
    if visual.get("topic") == "bi" and not is_part_of_aggregation(
  File "/omd/sites/monitor/lib/python3/cmk/gui/bi.py", line 68, in is_part_of_aggregation
    return get_cached_bi_compiler().is_part_of_aggregation(host, service)
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_compiler.py", line 254, in is_part_of_aggregation
    self._check_redis_lookup_integrity()
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_compiler.py", line 272, in _check_redis_lookup_integrity
    self.load_compiled_aggregations()
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_compiler.py", line 78, in load_compiled_aggregations
    self._check_compilation_status()
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_compiler.py", line 107, in _check_compilation_status
    self.prepare_for_compilation(current_configstatus["online_sites"])
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_compiler.py", line 157, in prepare_for_compilation
    self._bi_structure_fetcher.update_data(online_sites)
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_data_fetcher.py", line 98, in update_data
    self._fetch_missing_data(missing_program_starts)
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_data_fetcher.py", line 121, in _fetch_missing_data
    services = {
  File "/omd/sites/monitor/lib/python3/cmk/utils/bi/bi_data_fetcher.py", line 122, in <dictcomp>
    description: (set(tags), labels)

these additional infos: