connect to new user within PDB not working

[tale103108]

Oracle 18c

Connecting to PDB as 'sys', I cannot figure out how to connect to a schema other than 'sys'.

Here is what I have tried after logging into Oracle 18c CDB as 'sys':

ALTER SESSION SET CONTAINER= PDB;
conn myschema/mypasswd

--and also tried right from CDB

conn myschema/mypasswd@PDB;

Both approaches fail to get me connected as 'myschema' within the PDB.
Any suggestions?

[tale103108]

The issue was that the tnsnames.ora file had an incorrect HOST ip address for the tns alias.
All the SQL in the initial details now works as advertised.