Python login to email server authentication error

I am on a Linux machine. My company has an email exchange server which is already configured. I am using a Python script to try to login to the email server so that I can send an email programmatically. Here is what I have so far -

server = smtplib.SMTP('email-0.abc.com', 25)
server.set_debuglevel(1)
server.ehlo_or_helo_if_needed()    
server.login('abc/johndoe', 'pwd')

However, at the server.login command, I get an error as

raise SMTPException("No suitable authentication method found.")
SMTPException: No suitable authentication method found.

Anyone know what the problem is please?

Thanks