Steps to whitelist an email address or a domain
Microsoft 365 provides a layer of protection for your email account which diverts suspected spam emails to a separate folder away from the Inbox.
But it is always a possibility that you want some of those emails to come to the Inbox.
To bypass SPAM filtering, such emails and domains can be whitelisted.
Here are the steps to whitelist an email address or a domain.
Login to the Security Admin Center - Email & Collaboration - Policies & Rules - Threat policies - Anti-spam - Anti-spam inbound policy (Default) - Scroll down to the Allowed and blocked senders and domains and you can Edit allowed and blocked senders and domains