The security services are licensable. You must install a valid security license on the security appliance to activate security services. A valid security license is also required for support of SSLVPN with mobile devices such as smart phones and tablets.The Product Authorization Key (PAK) is required to validate the security license. You can find the license code from the Software License Claim Certificate that Cisco provides upon purchase of the security appliance.
Make sure that the security license is installed and does not expire before you configure security services. Go to the Device Management > License Management page to validate the security license or to renew the security license before it expires. See Installing or Renewing Security License, page 373.