Office 365 automatic spam filters are sometimes questionable, and some times seemingly legitimate emails end up in the SPAM FOLDER and not your Inbox and let's face it, how often do we check the spam folder these days. While this safeguard is usually helpful, missing an email from clients or friends can be a disaster. The whitelist allows domains to bypass the spam filter.
NOTE: You must log in to Office 365 as an Administrator to add domains to the whitelist.
1. Login at Portal.office.com and select 'Admin' then on the left menu at the bottom, select 'Admin' Centers' and then "Exchange" followed by "Mail Flow".
2. Click the plus sign icon and select "Bypass spam filtering" from the menu.
3. Here you can create a name for the rule such as 'Whitelist'
4. Select 'The sender' and 'domain is' from the "Apply this rule if".
5. Add the domain you want to allow access. Domain name example is google.com or microsoft.com, (never type www or the email address.)
6. If you have more than one domain to whitelist, use the same rule that you have now called whitelist.
That's it, log out, and your companies emails now whitelist those domains.