adding mail objectClass to schema

Hi all,

I am trying to create groups within in Openldap-2.4.34 to use for Gmail Active Directory Synch "GADs" I formed the ldif file with following attributes:

dn: cn=Google,ou=Group,dc=curry,dc=edu objectclass: groupOfUniqueNames cn: mail: description: uniqueMember: uniqueMember:

when I try to add the file I get the following error: adding new entry "cn=Google,ou=Group,dc=curry,dc=edu" ldap_add: Object class violation (65) additional info: attribute 'mail' not allowed

Thanks.