flask mail error “SMTPServerDisconnected('please run connect() first')” - python-3.x

Question

I am writing a little web application based on Miguel Grinberg's Flasky. I use the exact same code for user send reset password mail using gmail.
The following as my email.py file here i can implement mail sending function
def send_password_reset_email(user):
token = user.get_reset_password_token()
send_email(_('[Microblog] Reset Your Password'),
sender=current_app.config['ADMINS'][0],
recipients=[user.email],
text_body=render_template('email/reset_password.txt',
user=user, token=token),
html_body=render_template('email/reset_password.html',
user=user, token=token))
def send_async_email(app, msg):
with app.app_context():
mail.send(msg)
def send_email(subject, sender, recipients, text_body, html_body):
msg = Message(subject, sender=sender, recipients=recipients)
msg.body = text_body
msg.html = html_body
Thread(target=send_async_email,
args=(current_app._get_current_object(), msg)).start()
In routes.py file im getting email from the user and if the user email match then i well send the token to the user via mail
#bp.route('/reset_password_request', methods=['GET', 'POST'])
def reset_password_request():
if current_user.is_authenticated:
return redirect(url_for('main.index'))
form = ResetPasswordRequestForm()
if form.validate_on_submit():
user = User.query.filter_by(email=form.email.data).first()
if user:
send_password_reset_email(user)
flash(
_('Check your email for the instructions to reset your password'))
return redirect(url_for('auth.login'))
return render_template('auth/reset_password_request.html',
title=_('Reset Password'), form=form)
#bp.route('/reset_password/<token>', methods=['GET', 'POST'])
def reset_password(token):
if current_user.is_authenticated:
return redirect(url_for('main.index'))
user = User.verify_reset_password_token(token)
if not user:
return redirect(url_for('main.index'))
form = ResetPasswordForm()
if form.validate_on_submit():
user.set_password(form.password.data)
db.session.commit()
flash(_('Your password has been reset.'))
return redirect(url_for('auth.login'))
return render_template('auth/reset_password.html', form=form)
In model.py file in the user model i generate a token for a user and also check the user token
def get_reset_password_token(self, expires_in=600):
return jwt.encode(
{'reset_password': self.id, 'exp': time() + expires_in},
current_app.config['SECRET_KEY'],
algorithm='HS256').decode('utf-8')
#staticmethod
def varify_reset_password_token(token):
try:
id = jwt.decode(token, current_app.config['SECRET_KEY'],
algorithms=['HS256'])['reset_password']
except:
return
return User.query.get(id)
my flask mail setup is as follows config.py file
MAIL_SERVER = os.environ.get('MAIL_SERVER')
MAIL_PORT = int(os.environ.get('MAIL_PORT') or 25)
MAIL_USE_TLS = os.environ.get('MAIL_USE_TLS') is not None
MAIL_USERNAME = os.environ.get('MAIL_USERNAME')
MAIL_PASSWORD = os.environ.get('MAIL_PASSWORD')
ADMINS =['socialtraffic#gmail.com']
The following Error i get in the terminal
Traceback (most recent call last):
File "c:\python38\lib\threading.py", line 932, in _bootstrap_inner
self.run()
File "c:\python38\lib\threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "C:\Users\Ijaz Bacha\project\microblog1\app\email.py", line 9, in send_async_email
mail.send(msg)
File "c:\users\ijaz bacha\project\microblog1\venv\lib\site-packages\flask_mail.py", line 492, in send
message.send(connection)
File "c:\users\ijaz bacha\project\microblog1\venv\lib\site-packages\flask_mail.py", line 152, in __exit__
self.host.quit()
File "c:\python38\lib\smtplib.py", line 988, in quit
res = self.docmd("quit")
File "c:\python38\lib\smtplib.py", line 424, in docmd
self.putcmd(cmd, args)
File "c:\python38\lib\smtplib.py", line 371, in putcmd
self.send(str)
File "c:\python38\lib\smtplib.py", line 363, in send
raise SMTPServerDisconnected('please run connect() first')
smtplib.SMTPServerDisconnected: please run connect() first

Answer 1

I am also doing the same tutorial and ran into the same problem. I found the answer on Miguel's Blog:
You need two terminal windows.
The first terminal running your local mail server that emulates your emails being sent:
$(venv) python -m smtpd -n -c DebuggingServer localhost:8025
Your main flask terminal window with the following required commands (FLASK_DEBUG=1 is optional but highly recommended for troubleshooting):
$ export FLASK_APP=microblog.py
$ export FLASK_DEBUG=1
$ export MAIL_SERVER=localhost
$ export MAIL_PORT=8025
$ flask run
This solved my problems.

Answer 2

In my experience, a while ago I had a very similar issue that you you were having. After troubleshooting, I found out that my code worked when I would create a mail class, and call function like $mailclass.ehlo etc.
Based on the error its having an issue connecting or staying connected. Try calling the connect methods in the function itself and close of the connection after each email.

Answer 3

I decided to change the following line in the app/__init__.py file:
mail = Mail(app)
with:
mail = Mail()
mail.init_app(app)
Solved the issue for me