I am having problem that mail sent out from my server all goes to recipient's spam folder.
I am running Drupal sites on Linux server. CentOS w/ cPanel.
Our users cannot receive email as the mail went to the spam folder. (such as registration email, contact form email)
I was advised that I need to have PTR/rDNS record added for my host.
I then contact my datacenter to add PTR/rDNS thing, unfortunately, the datacenter said they are unable to do it.
So what can I do? Any other ways I can fix the problem?
*update, provided a screenshot from gmail spam folder