Defender for Office 365 and Exchange Online Protection monitor all emails hitting your domain and block harmful messages and spam. However, emails from legitimate sources can sometimes also be blocked for various reasons. In this scenario, as an admin, you want to whitelist the sender or the domain. In this post, you will learn how to whitelist a domain in Microsoft 365 and the necessary precautions you must take while doing so.

You can read the post on the following link: https://4sysops.com/archives/whitelist-a-domain-in-microsoft-365/