Standby Node SWITCHOVER_STATUS "NOT ALLOWED"

Hello everyone,

      I've configured Data guard from a RAC database (2 nodes ASM) to Standalone Database(1 node FileSystem)

After SwitchOver ,the New Active SWITCHOVER_STATUS is ok ,But Standby Node SWITCHOVER_STATUS is "NOT ALLOWED";

New Active(1 node FileSystem):

SQL> select process,CLIENT_PROCESS,status,thread#,sequence# from v$managed_standby;

PROCESS   CLIENT_P STATUS          THREAD#  SEQUENCE#

--------- -------- ------------ ---------- ----------

ARCH      ARCH     CLOSING               2         22

ARCH      ARCH     CLOSING               1         53

ARCH      ARCH     CLOSING               1         49

ARCH      ARCH     CLOSING               1         54

LNS       LNS      WRITING               1         55

SQL> SELECT SWITCHOVER_STATUS,OPEN_MODE,DATABASE_ROLE FROM V$DATABASE;

SWITCHOVER_STATUS    OPEN_MODE            DATABASE_ROLE

-------------------- -------------------- ----------------

TO STANDBY           READ WRITE           PRIMARY