SMTP not sending

Howdy, running HA 0.51.2, I have the notify portion set up correctly (notify.smtp component loads correctly upon startup), and am able to successfully trigger an SMTP notification, but nothing actually gets sent. In the logs, I see the following, and then nothing else:

2017-08-22 14:28:14 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: service=smtp_txt, service_call_id=1973478032-64, service_data=title=HA test title, message=HA test message, domain=notify>
2017-08-22 14:28:14 DEBUG (Thread-8) [homeassistant.components.notify.smtp] Building plain text email
2017-08-22 14:28:15 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=1973478032-64>

Here’s what I’m doing:
Domain:
notify
Service:
smtp_txt
Service Data:
{"title": "HA test title", "message": "HA test message"}

Calling the notify.smtp_txt service from an automation yields the same results.

Any help would be greatly appreciated.

If you’re using a local SMTP server, does that server’s logs show anything?

I am not using a local SMTP server. Here is my configuration.yaml:

notify:
  - name: smtp_txt
    platform: smtp
    sender: [email protected]
    recipient: [email protected]
    server: smtp.publicdomain.com
    port: 587
    timeout: 60
    username: [email protected]
    password: password
    sender_name: Home Assistant
    debug: True

I use swaks to test my configurations before implementing anything.
http://www.jetmore.org/john/code/swaks/

Thank you for that. I tested using swaks, and everything looks good: was able to receive my swaks test message. It seems like there’s something gummed up in Home Assistant. Going to try unleashing debug as default, instead of just for homeassistant.components.notify to see if anything stands out in the logs.

EDIT
Nothing much after:

2017-08-22 20:22:56 DEBUG (Thread-3) [homeassistant.components.notify.smtp] Building plain text email

I just set up smtp notify component and it worked as I would hope. Perhaps if you posted your automation it would help.

Here is my automation. Thank you in advance!

- action:
  - data:
      message: 'This is just a test'
    service: notify.smtp_txt
  alias: Notification Test
  condition: []
  id: '1503429606861'
  trigger:
  - entity_id: switch.tool_room__lights_switch
    from: 'off'
    platform: state
    to: 'on'

Is there some other automation that turns the lights on? Here is what I set up for a gas valve for the grill.

- alias: Gas Valve ON - Button 4 Pressed
  trigger:
    platform: event
    event_type: zwave.scene_activated
    event_data:
      entity_id: zwave.lr_remote
      scene_id: 7
  action:
    - service: switch.turn_on
      entity_id: switch.grill_switch
    - service: notify.HA
      data_template:
        message: 'Gas Valve OPEN'

Negative. This automation was specifically created to trigger a notification. I’m going to rebuild my HA server (full-blown Ubuntu on a netbook, instead of Hassbian 1.3 on a RPi3b). Maybe I mucked something while installing AppDaemon or dev build of OpenZwave. It’s just strange that the logs show that it’s building the email, but then it just goes dark, and no email is actually sent/received.

Will report back after the rebuild. Thanks again for your help!

Stood up an Ubuntu 16.04 machine, installed HA 0.51.2, copied the contents of /home/homeassistant/.homeassistant/ from the old machine to the new. Notifications are working properly. Thanks again!

Great news!!