Error when adding integration: Config flow could not be loaded: {"message":"Invalid handler specified"}

[JEReinhart]

Describe the bug
After installing via HACS and restarting HA, adding the integration produces this error:
Config flow could not be loaded: {"message":"Invalid handler specified"}

To Reproduce
Steps to reproduce the behavior:

1. Install via HACS
2. Restart HA
3. Attempt to add integration
4. See error

Expected behavior
Integration installs/shows config options

Screenshots

Desktop (please complete the following information):

• OS: Windows
• Browser Firefox

Additional context
Not sure if this is still maintained, but thought I would give it a try.

[frederickjh]

I am seeing this too. Hopefully the included log files at the bottom will help track this down @ryanmac8 . One is from this custom component. The other was logged by homeassistant.util.loop.

Home Assistant
Installation method Home Assistant OS
Core 2026.1.0
Supervisor 2026.03.3
Operating System 16.3
Frontend 20260107.0

Desktop (please complete the following information):

OS: Linux
Browser Firefox

Additional context
To be clear, I could not follow the Installation instruction in the README.md.

HACS (Recommended)

Have HACS installed, this will allow you to easily update
Add https://github.com/ryanmac8/HA-Mint-Mobile as a custom repository and Type: Integration
Click install under "Mint Mobile", restart your instance.

First the repository is now included in HACS so there is no need to add the repository. (I got a message to that effect from HACS.)
When the Mint Mobile custom component is selected in HACS there is only a "Download" button that I used to download it, no install button.
I was prompted to restart Home Assistant and did so. After that I still could not find an installation button in HACS and went to Settings > Devices & Services > and clicked the "+ Add Integration" button then searched for "Mint Mobile" and clicked on it. I then got a message
"Please wait, starting configuration wizard for Mint Mobile"
This is when I also got the same message as @JEReinhart 's in the screenshot above.

Error
Config flow could not be loaded: {"message":"Invalid handler specified"}

Log Files

This error originated from a custom integration.

Logger: homeassistant
Source: custom_components/tmobile_home_internet/utils.py:152
integration: T-Mobile Home Internet (documentation, issues)
First occurred: 16:53:50 (184 occurrences)
Last logged: 20:40:32

Error doing job: Task exception was never retrieved (task: None)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 294, in _handle_refresh_interval
    await self._async_refresh(log_failures=True, scheduled=True)
  File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 533, in _async_refresh
    self.async_update_listeners()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 200, in async_update_listeners
    update_callback()
    ~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 613, in _handle_coordinator_update
    self.async_write_ha_state()
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1024, in async_write_ha_state
    self._async_write_ha_state()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1149, in _async_write_ha_state
    self.__async_calculate_state()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1086, in __async_calculate_state
    state = self._stringify_state(available)
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1030, in _stringify_state
    if (state := self.state) is None:
                 ^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/sensor/__init__.py", line 569, in state
    value = self.native_value
            ^^^^^^^^^^^^^^^^^
  File "/config/custom_components/tmobile_home_internet/sensor.py", line 1261, in native_value
    return get_ssid_edit_index(self._hass)
  File "/config/custom_components/tmobile_home_internet/utils.py", line 152, in get_ssid_edit_index
    ssid_option = ssid.state
                  ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'state'

Logger: homeassistant.util.loop
Source: util/loop.py:137
First occurred: 20:37:31 (1 occurrence)
Last logged: 20:37:31

Detected blocking call to import_module with args ('custom_components.mintmobile.config_flow',) inside the event loop by integration 'config' at homeassistant/components/config/config_entries.py, line 195: return await super()._post_impl(request, data) (offender: /usr/src/homeassistant/homeassistant/loader.py, line 1307: return importlib.import_module(f"{self.pkg_path}.{platform_name}")), please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+config%22 For developers, please see https://developers.home-assistant.io/docs/asyncio_blocking_operations/#import_module Traceback (most recent call last): File "", line 198, in _run_module_as_main File "", line 88, in _run_code File "/usr/src/homeassistant/homeassistant/main.py", line 229, in sys.exit(main()) File "/usr/src/homeassistant/homeassistant/main.py", line 215, in main exit_code = runner.run(runtime_conf) File "/usr/src/homeassistant/homeassistant/runner.py", line 289, in run return loop.run_until_complete(setup_and_run_hass(runtime_config)) File "/usr/local/lib/python3.13/asyncio/base_events.py", line 712, in run_until_complete self.run_forever() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 683, in run_forever self._run_once() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 2050, in _run_once handle._run() File "/usr/local/lib/python3.13/asyncio/events.py", line 89, in _run self._context.run(self._callback, *self._args) File "/usr/local/lib/python3.13/site-packages/aiohttp/web_protocol.py", line 510, 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 214, 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 41, 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 83, in with_admin return await func(self, request, *args, **kwargs) 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/components/config/config_entries.py", line 188, in post return await self._post_impl(request, data) File "/usr/src/homeassistant/homeassistant/components/config/config_entries.py", line 195, in _post_impl return await super()._post_impl(request, data)