How to prevent email from being sent to spam. Let say email originating from a specific IP, for example, a website contact form, is delivered to spam. One step is to add an SPF record to the domain DNS.
In your domain registrar or host managing the nameservers, add a TXT record with the value:
v=spf1 mx a ip4:127.0.0.1 include:_spf.mailserver.com ~all
Change the ‘127.0.0.1’ to the IP address which is delivering to spam.
Change the ‘mailserver.com’ to actual mailserver for the domain.