Every new user registration email is going to spam folder

Please check this site https://www.healthboxhk.com. There is ssl installed on it. Yet, when a new user creates account on woocommerce, the mail is going to spam folder. What’s worse is that users are receiving mails from a random gmail id “[email protected]”. I have no idea who that user is. And why Woocommerce mails are sent using that email id. I am not sure what’s happening. Please help asap.