send_test_mail doesn't work when REDASH_USE_SSL set to true

[mkaramuk]

I deployed Redash by using community maintained helm chart (and used image tag as 10.1.0.b50633). After the deployment I tried send_test_mail but it throws WRONG_VERSION_NUMBER error:

redash@renhcv-redash-6854447469-xkjbw:/app$ ./manage.py send_test_mail 
Traceback (most recent call last):
  File "./manage.py", line 9, in <module>
    manager()
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/flask/cli.py", line 586, in main
    return super(FlaskGroup, self).main(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/flask/cli.py", line 426, in decorator
    return __ctx.invoke(f, *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/app/redash/cli/__init__.py", line 73, in send_test_mail
    subject="Test Message from Redash", recipients=[email], body="Test message."
  File "/usr/local/lib/python3.7/site-packages/flask_mail.py", line 491, in send
    with self.connect() as connection:
  File "/usr/local/lib/python3.7/site-packages/flask_mail.py", line 144, in __enter__
    self.host = self.configure_host()
  File "/usr/local/lib/python3.7/site-packages/flask_mail.py", line 156, in configure_host
    host = smtplib.SMTP_SSL(self.mail.server, self.mail.port)
  File "/usr/local/lib/python3.7/smtplib.py", line 1036, in __init__
    source_address)
  File "/usr/local/lib/python3.7/smtplib.py", line 251, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/local/lib/python3.7/smtplib.py", line 336, in connect
    self.sock = self._get_socket(host, port, self.timeout)
  File "/usr/local/lib/python3.7/smtplib.py", line 1044, in _get_socket
    server_hostname=self._host)
  File "/usr/local/lib/python3.7/ssl.py", line 423, in wrap_socket
    session=session
  File "/usr/local/lib/python3.7/ssl.py", line 870, in _create
    self.do_handshake()
  File "/usr/local/lib/python3.7/ssl.py", line 1139, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1091)
redash@renhcv-redash-6854447469-xkjbw:/app$

Mail servers configured properly. If I set REDASH_USE_TLS=true instead of REDASH_USE_SSL=true it works.

What is the difference between those two environment variables? I think SSL and TLS points the same thing. Is setting TLS is enough?

[eradman]

They are not the same thing, by experimenting this seems to be the difference

USE_SSL = smtps (usually port 465)
USE_TLS = smtp+tls (usually port 587)

[mkaramuk]

Sorry, I don't have much knowledge about mail servers. About this link, it says port 465 is a legacy and some legacy servers could be using it. Port 587 is the new one and the standard, right? In my case, my mail server is configured as SMTP + TLS and I should use USE_TLS.

I don't have access to the mail server. That's why I can't say how it is configured.

[eradman]

No, they are just different mechanisms

Port 465 is indicates a TLS-only connection
Port 587 is normal SMTP connection that accepts the STARTTLS command

[mkaramuk]

Thanks for the information.