ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

 root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin#

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin# more listener.ora

# listener.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora

# Generated by Oracle configuration tools.

LISTENER =

  (DESCRIPTION_LIST =

    (DESCRIPTION =

      (ADDRESS = (PROTOCOL = TCP)(HOST = pandba)(PORT = 1521))

      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

    )

  )

SID_LIST_LISTENER =

  (SID_LIST =

    (SID_DESC =

       (GLOBAL_DBNAME = GISUAT)

       (SID_NAME = GISUAT))

     (SID_DESC =

        (GLOBAL_DBNAME = PDBORCL)

        (SID_NAME = PDBORCL))

  )

ENABLE_GLOBAL_DYNAMIC_ENDPOINT_PDB_LISTENER=ON          # line added by Agent

VALID_NODE_CHECKING_REGISTRATION_PDB_LISTENER=SUBNET           # line added by Agent

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin#

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin# more tnsnames.ora

# tnsnames.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/tnsnames.ora

# Generated by Oracle configuration tools.

GISUAT =

  (DESCRIPTION =

    (ADDRESS = (PROTOCOL = TCP)(HOST = pandba)(PORT = 1521))

    (CONNECT_DATA =

      (SERVER = DEDICATED)

      (SERVICE_NAME = GISUAT)

    )

  )

PDBORCL =

  (DESCRIPTION =

    (ADDRESS = (PROTOCOL = TCP)(HOST = pandba)(PORT = 1521))

    (CONNECT_DATA =

      (SERVER = DEDICATED)

      (SERVICE_NAME = PDBORCL)

    )

  )

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin#

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin# more sqlnet.ora

# sqlnet.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/sqlnet.ora

# Generated by Oracle configuration tools.

#NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=11

SQLNET.ALLOWED_LOGON_VERSION_SERVER=11

root@pandba:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin#

oracle@pandba:~$ sqlplus gisadmin/password@PDBORCL

SQL*Plus: Release 12.1.0.2.0 Production on Mon Jan 27 08:07:05 2020

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Connected to:

Oracle Database 12c Standard Edition Release 12.1.0.2.0 - 64bit Production

SQL> show user;

USER is "GISADMIN"

SQL> exit

Disconnected from Oracle Database 12c Standard Edition Release 12.1.0.2.0 - 64bit Production

oracle@pandba:~$ m