Getting error in logstash output email plugin?

[talbehat (shubham jain)]

Error :

[2020-11-24T14:24:59,453][ERROR][logstash.outputs.email ][main] Something happen while delivering an email {:exception=>#<Net::SMTPAuthenticationError: 504 5.3.3 AUTH mechanism PLAIN not available

my output config :

email {
to => 'abc@abc.com'
from => 'abc@gmail.com'
subject => 'Alert - %{title}'
body => "Tags: %{tags}\n\Content:\n%{message}"
domain => 'smtp.gmail.com'
username => 'abc@gmail.com'
password => '**************'
port => 587
authentication => 'plain'
use_tls => 'true'
}

logstash version : 7.4

any idea why am i getting error ?

[Badger]

@talbehat

any idea why am i getting error ?

You have set authentication => 'plain' and the SMTP server is telling you that it does not support that.