Order emails flagged as spam

I have a common problem on all simplecart sites I have made, that the order email get flagged as spam. Has anyone got any suggested on how I can avoid this?

I’d definitely recommend setting up a third party mailer in the standard MODX settings. Something like Mandrill, Mailjet, Postmark or Amazon SES. That, combined with setting up SPF and DKIM records (plus DMARC optionally) should help with email delivery. Mail Tester is also incredibly useful for determining why an email might end up in spam.

Thanks - I used postmark, solved the problem.