Certificate-based connector configuration: Ensure that your on-premises email server is configured to work with a certificate to send out email to Microsoft 365, and also the Widespread-Identify (CN) or Subject Alternate Title (SAN) inside the certificate consists of a domain title that you've got registered in Microsoft 365, and you https://companyspage.com/story2466827/the-smart-trick-of-postal-smtp-setup-that-nobody-is-discussing