Ошибка при подключении к "smtp.gmail.com" через библиотеку 'smtplib' Python 3+

import smtplib as root
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from tkinter import *

screen = Tk()

screen.resizable(width=False, height=False)
screen.geometry('410x230')
screen.title('Spam to mail')

# Fucntion
def send_mail(event):
    L = login.get()
    P = password.get()
    U = url.get()
    To = toaddr.get()
    T = topic.get()
    M = mess.get()
    N = number.get()

    for value in range(int(N)):
        msg = MIMEMultipart()

        msg['Subject'] = T
        msg['From'] = L
        body = M
        msg.attach(MIMEText(body, 'plain'))

        server = root.SMTP_SSL(U, 465)
        server.login(L, P)
        server.sendmail(L, To, msg.as_string())
        server.quit()

        value += 1
        result['text'] = 'x' + str(value)

    # Events
    Tlogin = Label( text = 'Login:', font = 'Consolas' )
    login = Entry( screen, font = 'Consolas' )

    Tpassword = Label( text = 'Password:', font = 'Consolas' )
    password = Entry( screen, font = 'Consolas', show = '*' )

    Turl = Label( text = 'URL:', font = 'Consolas' )
    url = Entry( screen, font = 'Consolas' )

    Ttoaddr = Label( text = 'Кому:', font = 'Consolas' )
    toaddr = Entry( screen, font = 'Consolas' )

    Ttopic = Label( text = 'Topic message:', font = 'Consolas' )
    topic = Entry( screen, font = 'Consolas' )

    Tmess = Label( text = 'Message:', font = 'Consolas' )
    mess = Entry( screen, font = 'Consolas' )

    Tnumber = Label( text = 'Number of message:', font = 'Consolas' )
    number = Entry( screen, font = 'Consolas' )

    enter = Button( text = 'Send', font = 'Consolas', width = 18 )

    result = Label( text = 'Result:', font = 'Consolas' )

    # Packers
    Tlogin.grid( row = 0, column = 0, sticky = W, padx = 1, pady = 1 )
    login.grid( row = 0, column = 1, padx = 1, pady = 1 )

    Tpassword.grid( row = 1, column = 0, sticky = W, padx = 1, pady = 1 )
    password.grid( row = 1, column = 1, padx = 1, pady = 1 )

    Turl.grid( row = 2, column = 0, sticky = W, padx = 1, pady = 1 )
    url.grid( row = 2, column = 1, padx = 1, pady = 1 )

    Ttoaddr.grid( row = 3, column = 0, sticky = W, padx = 1, pady = 1 )
    toaddr.grid( row = 3, column = 1, padx = 1, pady = 1 )

    Ttopic.grid( row = 4, column = 0, sticky = W, padx = 1, pady = 1 )
    topic.grid( row = 4, column = 1, padx = 1, pady = 1 )

    Tmess.grid( row = 5, column = 0, sticky = W, padx = 1, pady = 1 )
    mess.grid( row = 5, column = 1, padx = 1, pady = 1 )

    Tnumber.grid( row = 6, column = 0, sticky = W, padx = 1, pady = 1 )
    number.grid( row = 6, column = 1, padx = 1, pady = 1 )

    enter.grid( row = 7, column = 0, padx = 1, pady = 1 )

    result.grid( row = 7, column = 1, padx = 1, pady = 1 )

    # Bind
    enter.bind( '<Button-1>', send_mail )

    # The end
    screen.mainloop()