You can enable and populate the following whitelists to minimize false positives:
Lets you list the sender domains that are permitted to bypass antispam scanning
Lets you list the email addresses to which inbound emails are permitted to bypass antispam scanning
If the Allowed Senders and Unfiltered Recipients lists are both enabled, Mail Security processes the Allowed Senders list first.
Email messages that are permitted to bypass antispam scanning are still scanned for risks and file filtering violations.
To configure whitelists
In the console on the primary navigation bar, click Policies.
In the sidebar under Antispam, click Whitelist.
In the content area, under Allowed Senders, check Bypass spam detection for messages sent from the following.
In the Email and domain addresses box, type the domains and email addresses (one per line) that are permitted to bypass spam detection.
Domain names must begin with either @ (at symbol) or an asterisk before the at symbol (for example, @mail.com or *@mail.com).
You can use DOS wildcard characters.
Under Unfiltered Recipients List, check Bypass spam detection for messages sent to the following.
In the Fully qualified email addresses box, type the fully qualified email addresses (one per line) to which email messages are permitted to bypass spam detection.
You can list up to 50 email addresses.
On the toolbar, click Deploy changes to apply your changes.