DBMS_DATAPUMP Error – Resolving API Inconsistencies in Oracle

I'm trying to do an impdp on a Amazon RDS Oracle instance using DBMS_DATAPUMP.

I'm following the steps described in the Amazon RDS guide (Importing Data into Oracle on Amazon RDS).

I've already copied successfully the dmp to the RDS instances.

This is my impdp job executed with awssys user:

-- IMPORT DATAPUMP
DECLARE
hdnl NUMBER;
BEGIN
hdnl := DBMS_DATAPUMP.OPEN( operation => 'IMPORT', job_mode => 'SCHEMA', job_name=>null);
DBMS_DATAPUMP.ADD_FILE( handle => hdnl, filename => '20180618_my_copied.dmp', directory => 'DATA_PUMP_DIR', filetype => dbms_datapump.ku$_file_type_dump_file);
DBMS_DATAPUMP.METADATA_FILTER(hdnl,'SCHEMA_EXPR','IN (''MYSCHEMA'')');
DBMS_DATAPUMP.START_JOB(hdnl);
END;
/      

I can't understand the meaning of the error displayed:

ORA-39002: operazione non valida
ORA-06512: a "SYS.DBMS_DATAPUMP", line 6224
ORA-06512: a line 7
39002. 00000 -  "invalid operation"
*Cause:    The current API cannot be executed because of inconsistencies
           between the API and the current definition of the job.
           Subsequent messages supplied by DBMS_DATAPUMP.GET_STATUS
           will further describe the error.
*Action:   Modify the API call to be consistent with the current job or
           redefine the job in a manner that will support the specified API.

This is the version of the source DB:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
"CORE   11.2.0.1.0  Production"
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production

This is the version of Amazon RDS instance:

Oracle Database 12c Standard Edition Release 12.1.0.2.0 - 64bit Production
PL/SQL Release 12.1.0.2.0 - Production
"CORE   12.1.0.2.0  Production"
TNS for Linux: Version 12.1.0.2.0 - Production
NLSRTL Version 12.1.0.2.0 - Production

EDIT: I've added version=COMPATIBLE to both the expdp command and DBMS_DATAPUMP options but error remains.

expdp system@source_db version=COMPATIBLE dumpfile=20180618_my.dmp logfile=20180618_my.log directory=DATA_PUMP_DIR CONSISTENT=Y  SCHEMAS=MYSCHEMA,MYSCHEMA2,MYSCHEMA3,MYSCHEMA4