Publish your domain’s DMARC document to avoid phishing and spoofing. If you’re utilizing a shared IP account from the provider like SendGrid, don’t put in place DKIM and DMARC. It forces your mail streams to have “area alignment” that might cause your emails to fail authentication and begin bouncing. https://gregorymeqbm.shoutmyblog.com/26502084/the-5-second-trick-for-server-security-expert