This plugin sets the PHPMailer Sender (return-path) the same as the From address if it’s not correctly set.
Mitigates the “via” and “The actual sender of” Notification in Outlook and stops email going to spam/junk because of the mismatch between From and Return-Path headers.
This usually occurs on shared hosting servers when local user / domain is used as default for the return-path header and WordPress only sets the From header.