BenRacicot on "[Plugin: WP Mail SMTP] Plugin works but email has message "may not have been sent by""

Hello, Awesome plugin. Just have a question regarding my emails once inside my gmail inbox. They have this message across the top. What exactly is making this get triggered?

This message may not have been sent by: ben@gmail.com Learn more Report phishing

http://wordpress.org/plugins/wp-mail-smtp/