SMTP not using mail settings when the Celery backend is used

[computergeek125]

I'm a bit at a loss for this one.

When I try to send password reset emails, I can see errors that look like this in the log (and no mail is delivered):

[2022-05-09 02:03:20,339: ERROR/ForkPoolWorker-7] djcelery_email_send_multiple[2cf90770-e0e1-445e-8cca-1deff82ea417]: Cannot reach CELERY_EMAIL_BACKEND django.core.mail.backends.smtp.EmailBackend
Traceback (most recent call last):
  File "/data/mediacms.io/lib/python3.9/site-packages/djcelery_email/tasks.py", line 40, in send_emails
    conn.open()
  File "/data/mediacms.io/lib/python3.9/site-packages/django/core/mail/backends/smtp.py", line 62, in open
    self.connection = self.connection_class(self.host, self.port, **connection_params)
  File "/usr/lib/python3.9/smtplib.py", line 253, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/lib/python3.9/smtplib.py", line 339, in connect
    self.sock = self._get_socket(host, port, self.timeout)
  File "/usr/lib/python3.9/smtplib.py", line 310, in _get_socket
    return socket.create_connection((host, port), timeout,
  File "/usr/lib/python3.9/socket.py", line 843, in create_connection
    raise err
  File "/usr/lib/python3.9/socket.py", line 831, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused
[2022-05-09 02:03:20,505: WARNING/ForkPoolWorker-7] djcelery_email_send_multiple[2cf90770-e0e1-445e-8cca-1deff82ea417]: Failed to send email message to ['<redacted>'], retrying. (ConnectionRefusedError(111, 'Connection refused'))
[2022-05-09 02:03:20,510: INFO/ForkPoolWorker-7] Task djcelery_email_send_multiple[2cf90770-e0e1-445e-8cca-1deff82ea417] succeeded in 0.3386348310014s: 0
[2022-05-09 02:03:20,512: INFO/MainProcess] Received task: djcelery_email_send_multiple[2cf90770-e0e1-445e-8cca-1deff82ea417]  ETA:[2022-05-09 02:06:20.506509+01:00]

If I run tcpdump when this is occuring, I can find: that its trying to talk to this server: static.93.10.69.159.clients.your-server.de - which appears to be the rDNS record of mediacms.io (which I remember was in the default configuration)

If I run the debugging test from the docs page, the entire process works - I receive the test email.

However, if I modify the test script to look like this (reflecting the Celery backend instead of the default Django backend), the email fails again.

from django.core.mail import EmailMessage
from django.conf import settings

#settings.EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
settings.EMAIL_BACKEND = 'djcelery_email.backends.CeleryEmailBackend'

email = EmailMessage(
    'title',
    'msg',
    settings.DEFAULT_FROM_EMAIL,
    ['<redacted>'],
)
email.send(fail_silently=False)

Extending that theory to the main config, if I set EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend' in the local_settings.py, emailing works, but (since I think this made it a synchronous action), pages that trigger email seem to take a bit longer to load.

I feel like I've done something incredibly stupid while setting this up, but I'm not sure what part of the config would cause it to use default settings only when a certain backend is in use.

I am running 9e7a7a7