I downloaded a Docker container for Oracle Database 18c XE.
When I run that container, after creating a pluggable database, I don't seem to be able to connect with new users I create:

As far as I can see I provided all necessary bits and bites to get these users at the ready. But what am I missing?
Here's the output of `lsnrctl status`, run in the container:
lsnrctl status
LSNRCTL for Linux: Version 18.0.0.0.0 - Production on 25-MAY-2021 11:57:33
Copyright (c) 1991, 2018, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 18.0.0.0.0 - Production
Start Date 25-MAY-2021 11:11:15
Uptime 0 days 0 hr. 46 min. 17 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/oracle/product/18c/dbhomeXE/network/admin/listener.ora
Listener Log File /opt/oracle/diag/tnslsnr/5854b834e19c/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=5854b834e19c)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=127.0.0.1)(PORT=5500))(Security=(my_wallet_directory=/opt/oracle/admin/XE/xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "XE" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
Service "XEXDB" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
Service "c323f0bfe62f0aaee053030011ac1ec5" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
Service "c323f7dc51bd0b68e053030011acc9a8" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
Service "mobydick" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
Service "xepdb1" has 1 instance(s).
Instance "XE", status READY, has 1 handler(s) for this service...
The command completed successfully
And this is my `tnsnames.ora` file content:
# tnsnames.ora Network Configuration File:
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)
LISTENER_XE =
(ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
XEPDB1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XEPDB1)
)
)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)
mobydick =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mobydick)
)
)
I created the pluggable database similar to this:
ALTER SESSION SET CONTAINER=CDB$ROOT;
CREATE PLUGGABLE DATABASE "mobydick" ADMIN USER "sa" IDENTIFIED BY "abc123" ROLES=(dba) FILE_NAME_CONVERT=('/opt/oracle/product/18c/dbhomeXE/dbs/mobydick/') STORAGE UNLIMITED
ALTER PLUGGABLE DATABASE mobydick OPEN READ WRITE