Office 365 provides protection for your email account with automatic filters that divert suspected spam to a separate folder away from the Inbox. While this safeguard is usually helpful it can create a problem.
Creating a whitelist tells the program which domains it should always allow through and eliminates the possibility of missing legitimate emails. You must log in to Office 365 as an Admin to add domains to the whitelist.
1. Click the “Admin” drop-down box at the top of the screen, select “Exchange” and click the “Mail Flow” heading.
2. Click the plus sign icon and select “Bypass spam filtering” from the menu.
3. Type a name for the rule in the appropriate text box. Something simple such as “Whitelist” suffices.
4. Select “The sender's domain is…” from the “Apply this rule if” drop-down box.
5. Enter the domains as follows:
wpengine.com and mail.wpengine.com