Hello,
it's a common problem but I tried all sollutions I could find and there was no sollution working for me.
I created a cdb without any pdbs. (I didn't create a non-cdb database because I read that this option will be deprecated soon). I don't need pdbs and thought everything I need should be possible with the cdb. Am I wrong?
The issue I have is: When I create a new user with the SYS user I can't login in SQL Developer with that new user. I still tried something like username, C##Username and even switched off the parameter sec_case_sensitive_logon for testing.
User Status is 'OPEN'. CDB attribute of the database is 'YES'.