Love the plugin. Recently developed a problem with e-mails being sent to gmail. Is this a problem with the plugin or an issue with the mail infrastructure on the system?
550-5.7.1 not RFC 2822 compliant. To reduce the amount of spam sent to Gmail,
<<< 550-5.7.1 this message has been blocked. Please review
<<< 550 5.7.1 RFC 2822 specifications for more information. ju7si4172521pbc.357 - gsmtp
554 5.0.0 Service unavailable