ORA-01116

I faced with those errors on 12c database. While I try to drop some tablespace it throws errors such as: SQL> DROP TABLESPACE MY_TABLESPACE INCLUDING CONTENTS AND DATAFILES; DROP TABLESPACE MY_TABLESPACEINCLUDING CONTENTS AND DATAFILES * ERROR at line 1: ORA-01116: error in opening database file 35 ORA-01110: data file 35: ‘/u01/app/oracle/product/12.1.0/dbhome_2/dbs/MY_TABLESPACE02_A.DBF’ ORA-27041: unable to open Continue reading