Error when adding the partition on oracle database table ORA-14074:

issue:
when adding the partition got the below error.

SQL> ALTER TABLE user1.test_table  ADD PARTITION "HMS_20180101" VALUES LESS THAN (TIMESTAMP '2018-01-01 00:00:00') TABLESPACE "user1";
ALTER TABLE user1.test_table  ADD PARTITION "HMS_20180101" VALUES LESS THAN (TIMESTAMP '2018-01-01 00:00:00') TABLESPACE "user1"
                                                           *
ERROR at line 1:
ORA-14074: partition bound must collate higher than that of the last partition

Root cause:
when we tried to add partition ,but the partition & partition range already exist on the same table,it will throw the error

Solution:
make sure to check the partition name & partition range and add the next partition appropriately

select partition_name from dba_tab_partitions where table_name='<> and table_owner="USR";