Hello, when wordpress sending mail notifications, the email is considered spam. I have several wordpress website on the same host and only the site with your theme exhibits this issue.
Did you tried to install theme on different server? To be honest, we have no idea what the problem might be as we have over 400 wp's and we did never met with anything like that. We think that this must be something on server side.
Comments
can you show us which mails exactly are going to spam? To be honest, it's first time when we met with something like that.