ORA-12541: TNS:no listener

LSNRCTL> status
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=0.0.0.0)(PORT=1539)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Solaris: Version 18.0.0.0.0 - Production
Start Date                26-MAY-2020 12:00:18
Uptime                    0 days 0 hr. 47 min. 28 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/soft/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/Ncsmaint/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=0.0.0.0)(PORT=1539)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "maint" has 1 instance(s).
  Instance "maint", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
LSNRCTL> exit
bash-4.1$ sqlplus /nolog

SQL*Plus: Release 18.0.0.0.0 - Production on Tue May 26 12:48:01 2020
Version 18.3.0.0.0

Copyright (c) 1982, 2018, Oracle.  All rights reserved.

SQL> connect username/pswd@dbid
ERROR:
ORA-12541: TNS:no listener


SQL> connect sys /as sysdba
Enter password:
Connected.
SQL> connect username/pswd@dbid
ERROR:
ORA-12541: TNS:no listener


Warning: You are no longer connected to ORACLE.
SQL>