Why it does not send email to the user that is currently logged in in the flask web app when it reaches a certain threshold?

Question

I created an iot gas leakage and electrical load monitoring flask web app. The problem is it does not send an email when the gas_value >= 0.2 and current_value_float >= 0.2to the user that is currently logged in in the web app.

|--website | |--pychache | |--static | |--templates | |--auth.py | |--email.py | |--init.py | |--models.py | |--views.py | |--app.py |--power.py |--mq6_module.py

here are my modifications in my code

init.py:

from flask_mail import Mail
mail = Mail()
def create_app():
    app = Flask(__name__)
    app.config.update(dict(
    MAIL_DEBUG = True,
    MAIL_SERVER = 'smtp.gmail.com',
    MAIL_PORT = 465,
    MAIL_USE_TLS = True,
    MAIL_USE_SSL = False,
    MAIL_USERNAME = '[email protected]',
    MAIL_PASSWORD = '****************',
))
    mail.init_app(app)
    

email.py:

from flask_mail import Message
from flask_login import current_user
from . import mail

def send_email( subject, body, recipient_email):

    msg = Message(subject,recipients=[recipient_email], sender= '[email protected]' )
    msg.body = body
    mail.send(msg)

To send message when it reaches certain threshold, I modify the views.py:

@views.route('/gas_value')
def gas_value():
    gas_value = mq6_modules[0].mq.MQPercentage()["GAS_LPG"]   # Assuming the first instance is used
    if gas_value >= 0.2:
        gas_reading = GasReading(value=gas_value)
        db.session.add(gas_reading)
        db.session.commit()
        send_email( 'High Gas Value Alert', 'Gas value has exceeded 0.2.', current_user.email)
    
    return jsonify({'gas_value': gas_value})

 @views.route('/current_value')
def current_value():
    current_value = powers[0].get_electricalsensor_readings()
    if current_value is not None:
        current_value_float = float(current_value)  # Convert current_value to float
    
        # Display the current value continuously
        response = {'current_value': current_value}

        # Store in the database if the value is greater than or equal to 0.2
        if current_value_float >= 0.2:
            current_reading = CurrentReading(value=current_value_float)
            db.session.add(current_reading)
            db.session.commit()
            send_email( 'High Current Value Alert', 'Current value has exceeded 0.2.', current_user.email)

        return jsonify(response)
    else:
        return jsonify({'current_value': 'Unavailable'})

I review email account security wherein I allowed access for less secure apps and set up app passwords for increased security but it states:

raise SMTPServerDisconnected("Connection unexpectedly closed")

smtplib.SMTPServerDisconnected: Connection unexpectedly closed

Answer 1

As I know, Google does not allow to use gmail smtp this way any more, at least I failed to resolve it (may be it will work for Google Workspace). https://support.google.com/accounts/answer/6010255?hl=en

Instead I used Yandex mail service. https://yandex.com/support/mail/mail-clients/others.html

May be there is email service where you host your app.