pythonsmtplib

Python freezes on smtplib.SMTP("smtp.gmail.com", 587)

I am attempting to create a script that send an email, using Gmail. However, my code freezes when the line below is ran:

smtplib.SMTP("smtp.gmail.com", 587)

It is before my username and password are entered, so it is nothing to do with my Gmail account. Why is this happening? I am using Python 3.6.3

The full code is below:

import smtplib

# Specifying the from and to addresses

fromaddr = 'XXX@gmail.com'
toaddrs  = 'YYY@gmail.com'

# Writing the message (this message will appear in the email)

msg = 'Enter you message here'

# Gmail Login

username = 'XXX@gmail.com'
password = 'PPP'

# Sending the mail  

server = smtplib.SMTP('smtp.gmail.com', 587)
server.starttls()
server.login(username,password)
server.sendmail(fromaddr, toaddrs, msg)
server.quit()
Solution

  • It is most likely a firewall or similar issue. On the machine having the issue, try running this on the command line:

    ping smtp.gmail.com

    Assuming that works, then try:

    telnet smtp.gmail.com 587

    I'm assuming a Linux machine with this command. You'll need to adapt for others. If that connects, type ehlo list and the command should show some info. Type quit to exit.

    If that doesn't work, then check your iptables. 

    sudo iptables -L

    This will either show something like ACCEPT all under Chain INPUT or if not, you'll need to ensure that you are accepting established connections with something like:

    ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED

    The output chain is often open, but you should check that too.

    If you are on AWS, check your security group isn't blocking outgoing connections.