Home Assistant release with the issue:

0.69.0

Last working Home Assistant release (if known):

Operating environment (Hass.io/Docker/Windows/etc.):

CentOS 7.4.1708 with Homeassistant running inside of a docker container, using the homeassistant/home-assistant:latest image.

Component/platform:

https://www.home-assistant.io/components/notify.matrix/
https://www.home-assistant.io/components/matrix/

Description of problem:
Matrix component logs in/joins rooms and I am able to trigger automations based on messages in the chat. However, I am not able to send messages to the chat using the notify.matrix component.

This is the error that shows up:

2018-05-11 18:11:21 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=notify, service=matrix, service_data=message=test message, service_call_id=140637933631360-78>
2018-05-11 18:11:21 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=matrix, service=send_message, service_data=target=['#hass:matrix.x.local'], message=test message, service_call_id=140637933631360-79>
2018-05-11 18:11:21 WARNING (SyncWorker_0) [homeassistant.components.matrix] Could not send message: setup is not done!
2018-05-11 18:11:21 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140637933631360-78>
2018-05-11 18:11:21 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140637933631360-79>

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

# Matrix component
matrix:
  homeserver: https://matrix.x.local
  username: "@hassbot:matrix.x.local"
  password: 12345
  rooms:
    - "#hass:matrix.x.local"
  commands:
    - expression: "My name is (?P<name>.*)"
      name: introduction

# notify.matrix component
notify:
  - platform: matrix
    name: matrix
    default_room: "#hass:matrix.x.local"

and the example automation from the docs

- alias: 'React to an introduction'
  trigger:
    platform: event
    event_type: matrix_command
    event_data:
      command: introduction
  action:
    service: notify.matrix
    data_template:
      message: "Hello "

Traceback (if applicable):

Additional information:

I also tested by calling notify.matrix service in the frontend with:

{"message": "test message"}

I looked a little bit into it, and it looks like _setup_done is initialized on https://github.com/home-assistant/home-assistant/blob/0.69.0/homeassistant/components/matrix.py#L118 and checked at https://github.com/home-assistant/home-assistant/blob/0.69.0/homeassistant/components/matrix.py#L346 but it is never actually changed from False to True. I'll try fixing that in the init function and submit a PR if the fix is that simple.