There is a problem between your ACS secret key for this client, and the secret key you've configured in LMS. These two keys must agree, and the LMS server must be added as a TACACS+ client of the ACS server. Double check the key values in LMS under Common Services > Server > Security > AAA Mode Settings and in ACS under Network Configuration > (NDG) > (LMS Server client) and make sure the key values agree.