The AE server did not come up or the DB Utilities (DB Archive / Reorg / Unload) do not start.
The following error appears in the log file:
20210316/170210.476 - U00029108 UCUDB: SQL_ERROR Database handles DB-HENV: 2420510 DB-HDBC: 0
20210316/170210.477 - U00003591 UCUDB - DB error info: OPC: 'OCIEnvNlsCreate' Return code: 'ERROR'
20210316/170210.477 - U00003592 UCUDB - Status: '' Native error: '1804' Msg: 'Error while trying to retrieve text for error ORA-01804'
20210316/170210.477 - U00003590 UCUDB - DB error: 'OCIEnvNlsCreate', 'ERROR ', '', 'Error while trying to retrieve text for error ORA-01804'
20210316/170210.477 - U00003611 DB OPEN executed. Return Code = '0000003590'
20210316/170210.477 - U00003620 Routine 'UCMAIN_R' forces trace because of error.
20210316/170210.477 - U00003590 UCUDB - DB error: 'OCIEnvNlsCreate', 'ERROR ', '', 'Error while trying to retrieve text for error ORA-01804'
Release : 12.3 / 21.0
Component : Automation Engine / DB Utilities
This Oracle error is an indication that an environmental variable is not set correctly.
Check the out put of the Unix command 'env' and check how variables like $ORACLE_HOME are set in .bashrc or .bash_profile.