Unable to send e-mail using python - python-3.x

Question

I'm running Rasbian Buster and use Msmtp to send emails from the command line and it works just fine.
When I try to send emails using Python it fails miserably, I've tried various python examples from the net, e.g.
# Sending Email Alerts via Zoho
#
#
import smtplib
server = smtplib.SMTP_SSL('smtp.zoho.com',port=465) #server for sending the email
server.ehlo() # simple starting of the connection
server.login('test_email#zoho.com','pwd_12345') # login credentials and password
msg = """From:test_email#zoho.com
Subject: Test Email \n
To: recipient_email#gmail.com \n"""
# This is where the email content goes. It could be information about the error, time of day, where in the script, etc.
server.sendmail('test_email#zoho.com','recipient_email#gmail.com',msg) # this is where the email is sent to the recipient
server.quit() # exit the connection
... but I unfortunately I always get the following error:
Traceback (most recent call last):
File "/usr/lib/python3.7/smtplib.py", line 387, in getreply
line = self.file.readline(_MAXLINE + 1)
File "/usr/lib/python3.7/socket.py", line 589, in readinto
return self._sock.recv_into(b)
ConnectionResetError: [Errno 104] Connection reset by peer
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/pi/test_email_python_06.py", line 6, in <module>
server = smtplib.SMTP('smtpauths.bluewin.ch',port=465) #server for sending the email
File "/usr/lib/python3.7/smtplib.py", line 251, in __init__
(code, msg) = self.connect(host, port)
File "/usr/lib/python3.7/smtplib.py", line 338, in connect
(code, msg) = self.getreply()
File "/usr/lib/python3.7/smtplib.py", line 391, in getreply
+ str(e))
smtplib.SMTPServerDisconnected: Connection unexpectedly closed: [Errno 104] Connection reset by peer
As a newbee any hint would be appreciated.
Thanks!

Answer 1

This issue has been solved!
My ISP uses SSL on port 465 and my command line email client MSMTP works just great using that.
As I was so desperate, so that I startet to play around and just use port 25 and "Bingo" the sending of emails works now just fine, the funny part is that my ISP suggest to use port 465.