ORA-20000: index or partition is in unusable state

ORA-20000: index "SAPSR3"."/xxxxxxxxxxxx"  or partition of such index is in unusable state

Error in log file:

BR0301E SQL error -20000 at location stats_tab_collect-20, SQL statement: 'BEGIN DBMS_STATS.GATHER_TABLE_STATS (OWNNAME => '"SAPSR3"', TABNAME => '"xxxxxxx"', ESTIMATE_PERCENT => 10, METHOD_OPT => 'FOR ALL COLUMNS SIZE 1'
ORA-20000: index "SAPSR3"."/xxxxxxxxxxxx"  or partition of such index is in unusable state
ORA-06512: at "SYS.DBMS_STATS", line 14537
ORA-06512: at "SYS.DBMS_STATS", line 14558
ORA-06512: at line 1
BR0886E Checking/collecting statistics failed for table SAPSR3.xxxxxx


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#sqlplus / as sysdba

SQL> select table_name, index_name from dba_indexes where status = 'UNUSABLE';

TABLE_NAME                     INDEX_NAME
------------------------------ ------------------------------
/BIC/B0000219000               /BIC/B0000219000KE

SQL> ALTER INDEX "SAPSR3"."/BIC/B0000219000KE" REBUILD; (Be carreful with big tables)
SQL> exit
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Redo the statistics...