ORA-22288: file or LOB operation FILEOPEN failed, access denied

I would like to store an xml file in oracle database and I did the following :

create table MyTab (filename varchar(64), xml XMLType);

create or replace directory XML开发者_运维问答_DIR as 'C:\Users\XXX\XXX\Folder\xml';

insert into MyTab VALUES ('file.xml', xmltype(bfilename('XML_DIR','file.xml'),nls_charset_id('AL32UTF8')));

However i have this error : ORA-22288: file or LOB operation FILEOPEN failed, access denied

Can someone explain what is wrong, please?