As a web designer, have you been stymied by your inability to get sendmail/postfix working on more recent versions of macOS? If so, maybe you need to take a different route. This step-by-step tutorial will help you install an SMTPD server on your machine, which is independent of macOS’s built-in sendmail and postfix binaries. Visit this URL:
https://www.billkochman.com/Single-Docs/smptd-server-configuration-tutorial-macos.html