If I send emails from an email-enabled object within Salesforce, e.g., case, the emails do not always get delivered to recipients. I have discovered that one or two of the recipients have these emails quarantined on account of "anti-spoofing" rules set on the email server. Is there a setting in my salesforce org that I should have enabled/disabled in order to stop this issue occurring? In particular, I do not have Email Security Compliance enabled.
You can enable "Enable Sender ID compliance" under Deliverability, the downside is that all the emails will show as coming from firstname.lastname@example.org.
Another option would be to implement the Email Relay feature.
You can read more about this here :