I set up a Postfix/Dovecot virtual domain mail server on a Centos 7 Droplet. I am running 2 domains we’ll call domain.com and domain.org. My server is domain.com and domain.org is pointed to the same IP I have MX and SPF records as well as a mail CNAME DNS record. I also installed MySQL and Roundcube Web Mail client. I built SSL certificates for my domains but I am using domain.com actually mail.domain.com to serve up smtp and imap using SSL ports 993 and 465. Everything works great except when I send an email to my gmail.com account using domain.org the email goes to junk/spam. Sending an email from domain.com goes to the inbox as expected. I added an SPF record to my domains but that didn’t change anything. I currently use a hosting service for my main domain which is not involved in this exercise and uses a common secure mail server address that is different from my domain and those emails get delivered to my gmail inbox correctly. I am sure there is something I need to configure in Postfix but have not figured it out yet. Hoping someone will recognize the issue and help me out. Thanks in advance.
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