SQL & PL/SQL

I have a materialized view that was created with syntax below. I have tried the following to refresh without success. The last DDL is last friday (when I created the materialized view) and the data is stale. What am I doing wrong?

BEGIN
DBMS_SNAPSHOT.REFRESH(
LIST => 'schema.MV'
,PUSH_DEFERRED_RPC => TRUE
,REFRESH_AFTER_ERRORS => FALSE
,PURGE_OPTION => 1
,PARALLELISM => 0
,ATOMIC_REFRESH => TRUE
,NESTED => FALSE);
END;

or

exec DBMS_MVIEW.REFRESH (list=>'schema.MV',method=>'?');

or

exec DBMS_MVIEW.REFRESH (list=>'schema.MV',method=>'C');


CREATE MATERIALIZED VIEW MV
TABLESPACE TBLSP
PCTUSED 0
PCTFREE 10
INITRANS 2
MAXTRANS 255
STORAGE (
INITIAL 64K
NEXT 1M
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
BUFFER_POOL DEFAULT
)
NOCACHE
LOGGING
NOCOMPRESS
NOPARALLEL
BUILD IMMEDIATE
REFRESH FORCE ON DEMAND
WITH PRIMARY KEY
AS
SELECT * FROM schema.table@dblink;