SSL error while sending email using smtp with Python

Question

I want to send an email using outlook. The code is as follows:

import smtplib
from email.message import EmailMessage

msg = EmailMessage()
msg['From'] = '*******'
msg['Subject'] = 'Some subject here'
msg['To'] = '********'
        
msg.set_content('Some text here')

with smtplib.SMTP_SSL('smtp-mail.outlook.com', 587) as smtp:
    smtp.login('******', '****')
    smtp.send_message(msg)
    print('Email sent!')

I get the following error:

---------------------------------------------------------------------------
SSLError                                  Traceback (most recent call last)
<ipython-input-8-4d5956f55c88> in <module>
      6 msg.set_content('Some text here')
      7 
----> 8 with smtplib.SMTP_SSL('smtp-mail.outlook.com', 587) as smtp:
      9     smtp.login('sender_email', 'password')
     10     smtp.send_message(msg)

~/anaconda/envs/quant2/lib/python3.6/smtplib.py in __init__(self, host, port, local_hostname, keyfile, certfile, timeout, source_address, context)
   1029             self.context = context
   1030             SMTP.__init__(self, host, port, local_hostname, timeout,
-> 1031                     source_address)
   1032 
   1033         def _get_socket(self, host, port, timeout):

~/anaconda/envs/quant2/lib/python3.6/smtplib.py in __init__(self, host, port, local_hostname, timeout, source_address)
    249 
    250         if host:
--> 251             (code, msg) = self.connect(host, port)
    252             if code != 220:
    253                 self.close()

~/anaconda/envs/quant2/lib/python3.6/smtplib.py in connect(self, host, port, source_address)
    334         if self.debuglevel > 0:
    335             self._print_debug('connect:', (host, port))
--> 336         self.sock = self._get_socket(host, port, self.timeout)
    337         self.file = None
    338         (code, msg) = self.getreply()

~/anaconda/envs/quant2/lib/python3.6/smtplib.py in _get_socket(self, host, port, timeout)
   1037                     self.source_address)
   1038             new_socket = self.context.wrap_socket(new_socket,
-> 1039                                                   server_hostname=self._host)
   1040             return new_socket
   1041 

~/anaconda/envs/quant2/lib/python3.6/ssl.py in wrap_socket(self, sock, server_side, do_handshake_on_connect, suppress_ragged_eofs, server_hostname, session)
    405                          suppress_ragged_eofs=suppress_ragged_eofs,
    406                          server_hostname=server_hostname,
--> 407                          _context=self, _session=session)
    408 
    409     def wrap_bio(self, incoming, outgoing, server_side=False,

~/anaconda/envs/quant2/lib/python3.6/ssl.py in __init__(self, sock, keyfile, certfile, server_side, cert_reqs, ssl_version, ca_certs, do_handshake_on_connect, family, type, proto, fileno, suppress_ragged_eofs, npn_protocols, ciphers, server_hostname, _context, _session)
    815                         # non-blocking
    816                         raise ValueError("do_handshake_on_connect should not be specified for non-blocking sockets")
--> 817                     self.do_handshake()
    818 
    819             except (OSError, ValueError):

~/anaconda/envs/quant2/lib/python3.6/ssl.py in do_handshake(self, block)
   1075             if timeout == 0.0 and block:
   1076                 self.settimeout(None)
-> 1077             self._sslobj.do_handshake()
   1078         finally:
   1079             self.settimeout(timeout)

~/anaconda/envs/quant2/lib/python3.6/ssl.py in do_handshake(self)
    687     def do_handshake(self):
    688         """Start the SSL/TLS handshake."""
--> 689         self._sslobj.do_handshake()
    690         if self.context.check_hostname:
    691             if not self.server_hostname:

SSLError: [SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:852)

Answer 1

Microsoft Outlook uses STARTTLS when sending an email. So you need to replace smtplib.SMTP_SSL with smtplib.SMTP and you need to call starttls

reference: smtplib.SMTP.starttls

import smtplib
from email.message import EmailMessage

sender = 'somename@outlook.com'
recipient = 'somename@gmail.com'

msg = EmailMessage()
msg.set_content('this is a test')
msg['From'] = 'somename@outlook.com'
msg['To'] = 'somename@gmail.com'
msg['Subject'] = 'test email'

with smtplib.SMTP('smtp.office365.com', 587) as server:
    server.ehlo()
    server.starttls()
    server.ehlo()
    server.ehlo()
    server.login('your_login', "your_password", initial_response_ok=True) 
    server.ehlo()
    server.sendmail(sender, recipient, msg.as_string())
    print('Email sent!')
    server.close()

Here is the Outlook message in my Gmail account.

I noted that I had to change my Outlook password, because it had a \n, which Python read as a new line.

----------------------------------------
My system information
----------------------------------------
Platform:       macOS
OS Version:     10.15.7
Python Version: 3.9
----------------------------------------

Your question didn't identity the type of Outlook account you have.

1. Free account
2. Corporate account

You stated in the comments below that your error message included ask your email administrator. I haven't seem this message with the Free account so I'm assuming that you might have a Corporate account. If you do have the latter please review this Enable or disable authenticated client SMTP submission, because an email administrator would need to enable Authenticated SMTP on your corporate account.