Is there any Katalon gmail plugin alternative?

In order to read latest email in gmail for password verification link, I tried using gmail plugin but it throws an error (console message: multipart message)

Therefore, I tried creating new function to read multipart message, now I am getting new error (console message: multipart/MIXED;

snippet from function:

                           String subject = message.getSubject();
			String from = message.getFrom()[0].toString();
			String body = message.getContentType()
			println body

How shall I proceed to get the content/text of email?