Activating DKIM Management Email Security allows an unlimited number of DKIM entries to be defined. To activate DKIM Management for Email Security: Add all your selectors to the domain's DKIM Management page. See Adding New DKIM Selector to your Domain. If required, insert DNS NS records for your subdomains. Click Save & Update to activate the selectors. Once the selectors are activated, the system shows your Name Servers. Email Security verifies the updated DNS NS record and activates DKIM Management.