Can you Check the Authentication Log?
Is test connection to HSS successful from Load balance configuration ?
there are some documents in Oracle Support for that issue. Did you check them?
is this happening to all users?
Hyperion FDM Error: "An Error Occurred Logging on to the System- Security Authentication Failure" For All Users Except Admin (Doc ID 1387011.1)
Actuall everyone can access the FDM, but one of my client was unable to login..
are you using native directory or MSAD?
check that password are not expired.