This ins’t something Email Users has control over. In most hosting environments, email headers sent through the web infrastructure don’t have any resemblance to the originating domain (your web site) which is why email typically get classified as spam. There is also the possibility that another organization which uses the same infrastructure you’re using has been sending spam so everything coming from the hosting provider’s domains is now marked as spam.
The best way to ensure your email from WordPress isn’t marked as spam is to use some sort of SMTP plugin to send email (there are several available). Doing this will ensure your email is routed through the same process as if you were sending email from your mail client.
