I have oracle database 12c installed.
I am trying to create a database in it which will hold tables etc.
For that , I am doing below.
In SQL PLUS, connect as system.

Now , I open SQL Developer on the same machine and try to connect to the Database that i connected using above but get error Invalid password or username. As below.

I referred, below post but that did not help.
Oracle 12c Database - New user Creation
https://dba.stackexchange.com/questions/60806/oracle-12c-create-user
In Oracle 11G, above steps used to work without any issues.
Please help.
Regards,
RVS