Summary Configure the Shared mode for Oracle connection, it failed and returned ORA-12523, found out it is mandatory to configure local listener.
Encountered SQL developer- the network adapter could not establish the connection, it is quite simple, the Oracle listener was not start up.
Summary Encountered problem cannot login Oracle by login name and password “system/oracle”, resolved this issue by changed the kernal parameter kernel.sem in sysctl.conf.
SQL Developer is the GUI software to connect Oracle DB, installed on AWS Ubuntu and tested the connection to RDS.
Created the Oracle EE on the AWS RDS, tried different methods to connect the created AWS RDS through internet.