smtplib issues when using celery to send mails async

[Lunarequest]

I have been trying to send a user activation mail with flask-mailman and come across this error. I don't quite understand why it happens. have I misconfigured something?
the function that causes this error

@celery.task
def send_email(username, email, url):
    app = create_app()
    with app.app_context():
        with mail.get_connection(backend="smtp") as connection:
            msg = EmailMessage(
                "Activate Your account",
                f"{username} please confirm your email by going to {url}",
                app.config["MAIL_USER"],
                [email],
                connection=connection,
            )
            msg.send(fail_silently=False)

2021-04-11 18:05:21,818: ERROR/ForkPoolWorker-4] Task argboard.routes.auth.auth.send_email[8c6ab451-ba1a-4780-80aa-76916670c8ec] raised unexpected: SMTPServerDisconnected('please run connect() first')
Traceback (most recent call last):
  File "/home/nullrequest/.local/share/virtualenvs/argboard-Q0PubHYB/lib/python3.9/site-packages/celery/app/trace.py", line 405, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/home/nullrequest/.local/share/virtualenvs/argboard-Q0PubHYB/lib/python3.9/site-packages/celery/app/trace.py", line 697, in __protected_call__
    return self.run(*args, **kwargs)
  File "/home/nullrequest/argboard/argboard/routes/auth/auth.py", line 28, in send_email
    with mail.get_connection(backend="smtp") as connection:
  File "/home/nullrequest/.local/share/virtualenvs/argboard-Q0PubHYB/lib/python3.9/site-packages/flask_mailman/backends/base.py", line 50, in __enter__
    self.open()
  File "/home/nullrequest/.local/share/virtualenvs/argboard-Q0PubHYB/lib/python3.9/site-packages/flask_mailman/backends/smtp.py", line 67, in open
    self.connection.starttls(keyfile=self.ssl_keyfile, certfile=self.ssl_certfile)
  File "/usr/lib/python3.9/smtplib.py", line 753, in starttls
    self.ehlo_or_helo_if_needed()
  File "/usr/lib/python3.9/smtplib.py", line 604, in ehlo_or_helo_if_needed
    if not (200 <= self.ehlo()[0] <= 299):
  File "/usr/lib/python3.9/smtplib.py", line 444, in ehlo
    self.putcmd(self.ehlo_msg, name or self.local_hostname)
  File "/usr/lib/python3.9/smtplib.py", line 371, in putcmd
    self.send(str)
  File "/usr/lib/python3.9/smtplib.py", line 363, in send
    raise SMTPServerDisconnected('please run connect() first')
smtplib.SMTPServerDisconnected: please run connect() first

[waynerv]

Sorry I've never used celery, so I'll need some time to investigate the problem you describe.

[jwag956]

FWIW - I can run with Celery with no problems. One possible thing I see is that you are doing the create_app() inside the celery task - not sure why you would do that - presumably, you are using Flask and should have already created the 'app' and use that SAME global app to set up a context.