SMTP service not showed

Hi, i’ve setted SMTP server on Configuration.yaml,
but i see this log:

2023-03-07 12:54:30.682 ERROR (MainThread) [homeassistant.components.notify] Error setting up platform smtp
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/notify/legacy.py", line 92, in async_setup_platform
    notify_service = await hass.async_add_executor_job(
  File "/usr/local/lib/python3.10/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/components/smtp/notify.py", line 92, in get_service
    if mail_service.connection_is_valid():
  File "/usr/src/homeassistant/homeassistant/components/smtp/notify.py", line 154, in connection_is_valid
    server = self.connect()
  File "/usr/src/homeassistant/homeassistant/components/smtp/notify.py", line 144, in connect
    mail.starttls(context=ssl_context)
  File "/usr/local/lib/python3.10/smtplib.py", line 771, in starttls
    raise SMTPNotSupportedError(
smtplib.SMTPNotSupportedError: STARTTLS extension not supported by server.

What’s the meaning?

Your mail server does not support encryption.