ORA-12578: TNS:wallet open failed

@dbfs

Getting this error, when trying to use this:

sqlplus /@dbfs - tns alias for my db

where as sqlplus scott/tiger@dbfs is working

this is my sqlnet.ora:

ENCRYPTION_WALLET_LOCATION=(SOURCE=(METHOD = FILE)(METHOD_DATA=(DIRECTORY = /ora/acfs/wallet/)))

#SQLNET.WALLET_OVERRIDE = TRUE

SSL_CLIENT_AUTHENTICATION = FALSE

SSL_VERSION = 0

NAMES.DIRECTORY_PATH= (TNSNAMES)

Please assist/advies, what needs to be done, to make it work.

Thanks in advance.