Automations not working anymore

I recently upgraded my Hassbian installation on a Pi3 to the newest version 0.44.1 and upgrade the OS (sudo apt-get && sudo apt-get dist-upgrade). Raspberry firmware is version 4.3.24 (rpi-update).

Since then I get all kinds of errors in my log. If I exclude all automations, then HA starts without problems, but as soon as I include automations then the errors are occurring again.

The following errors have been logged this session:
2017-05-11 22:19:16 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.4/asyncio/tasks.py", line 233, in _step
    result = coro.throw(exc)
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/setup.py", line 60, in async_setup_component
    return (yield from task)
  File "/usr/lib/python3.4/asyncio/futures.py", line 388, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.4/asyncio/tasks.py", line 286, in _wakeup
    value = future.result()
  File "/usr/lib/python3.4/asyncio/futures.py", line 277, in result
    raise self._exception
  File "/usr/lib/python3.4/asyncio/tasks.py", line 237, in _step
    result = next(coro)
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/setup.py", line 155, in _async_setup_component
    conf_util.async_process_component_config(hass, config, domain)
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/config.py", line 548, in async_process_component_config
    p_validated = component.PLATFORM_SCHEMA(p_config)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 221, in __call__
    return self._compiled([], data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 538, in validate_dict
    return base_validate(path, iteritems(data), out)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 315, in validate_mapping
    cval = cvalue(key_path, value)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 716, in validate_callable
    return schema(data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/validators.py", line 262, in __call__
    v = schema(v)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 221, in __call__
    return self._compiled([], data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 575, in validate_sequence
    cval = validate(index_path, value)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 716, in validate_callable
    return schema(data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/validators.py", line 224, in __call__
    return schema(v)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 221, in __call__
    return self._compiled([], data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 716, in validate_callable
    return schema(data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/validators.py", line 262, in __call__
    v = schema(v)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 221, in __call__
    return self._compiled([], data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 716, in validate_callable
    return schema(data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 221, in __call__
    return self._compiled([], data)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 538, in validate_dict
    return base_validate(path, iteritems(data), out)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 315, in validate_mapping
    cval = cvalue(key_path, value)
  File "/srv/homeassistant/lib/python3.4/site-packages/voluptuous/schema_builder.py", line 716, in validate_callable
    return schema(data)
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/helpers/config_validation.py", line 222, in service
    if valid_entity_id(value):
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/core.py", line 66, in valid_entity_id
    return ENTITY_ID_PATTERN.match(entity_id) is not None
TypeError: expected string or buffer

Problem solved. It was a faulty automation with notification and iOS.