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Summary
Question
Did the customer change any db passwords?
I saw the following errors in the logs:
'ORA-28000: the account is locked'
It seems some of their db users is locked, this can happen if you try to login with an incorrect password for several times.
Answer
Let's check the db accounts status with the following commands:
su - oracle
sqlplus "/as sysdba"
SQL> select username, expiry_date, account_status from dba_users;
Please get the output of this SQL and check which account is locked.
You can then unlock it with the following query:
SQL> alter user <LOCKED_USERNAME> account unlock;