Add the lines shown below to the Security.properties file.
# Remove Preferred Mail Host from UI *.NewOrganizationPage6.PreferredMailHostProperty=INVISIBLE *.NewOrganizationSummaryPage.PreferredMailHostSummaryProperty=INVISIBLE *.OrgProperties.MailHostName=INVISIBLE *.OrgProperties.MailHostNameText=INVISIBLE *.OrgProperties.MailHostValue=INVISIBLE
CAUTION: You may add lines to this file for your own customization, but do not edit the lines already present. Editing existing lines could result in exceptions being thrown on the console.
Redeploy the edited Security.properties file to the Web container used by the Delegated Administrator console.
Before the change can take effect, you must run the script that deploys the customized Security.properties file to your Web container.
For instructions on how to deploy a customized properties file to a particular Web container, see To Deploy a Customized Configuration File.