ORA-01654: unable to extend index PS6_MDS.MDS_ATTRIBUTES_U2 by 1024 in tablespace PS6_MDS

You need to add more space to your datafile/tablespace, or extend the index.

SQL> alter index APPLSYS.SYS_IOT_TOP_34179 storage (maxextents unlimited);

SQL> ALTER TABLESPACE <tablespace name> ADD DATAFILE '<full path and file name>' SIZE <integer> <K|M>; 

Note: 1025288.6 - How to Diagnose and Resolve UNABLE TO EXTEND Errors
https://metalink2.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=1025288.6

Note: 19049.1 - OERR: ORA 1654 unable to extend index by for tablespace
https://metalink2.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=19049.1

Note: 762273.1 - ORA-1654: unable to extend index 
https://metalink2.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=762273.1