Allow List
Adding senders and domains to the Allow List is a way of minimizing false positives for users. A false positive is when a user receives an email they know is clean, but has been flagged as malicious by Email Security and has had a banner applied to it. You have the option of adding individual email addresses you know to be clean, or you can add entire domains.
Important
When you add a sender's email address or a domain to the Allow List, it is not analyzed by Email Security and is delivered directly to the user's inbox. So be sure that the email or domain is from a trusted source.
The Allow List only exists on customer level. As a customer admin, you can go to Configuration > Mail Flow > Allow List to view the Allow List, add a sender to the Allow List, or add a domain to the Allow List.
Note
There is a quick action option from the MSP level to add both senders and domains to the Allow List. This can be done from the Incidents page by selecting the allow sender 
icon or the add domain 
icon from the Actions column.