Domain locking is available only for domains registered through Yahoo! after January 22, 2001 (or, for Merchant Solutions customers, after March 23, 2001). If you redelegated a domain you registered elsewhere for use with your Yahoo! plan, domain locking and some Domain Control Panel features will be unavailable. If you'd like to activate locking for a redelegated domain, please contact your domain registrar and ask about the availability of this feature.