Official comment

Try to physically connect using sqlplus to the database.
export ORACLE_HOME=/u01/app/oracle/product/12.1.0/dbhome_2
export PATH=$ORACLE_HOME/bin:$PATH
export TNS_ADMIN="/u01/app/oracle/product/12.1.0/dbhome_2/network/admin"
export LD_LIBRARY_PATH="/tmp/par-oracle/cache-388dc02a07153078cbfbdef53b70738a8e8cb376"
sqlplus SYSTEM@soadb
If you get this ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
Your listener does not know the instance/service name you refer to in the tnsnames. Make sure to register the database to the listener?
lsnrctl status:
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date 01-JUN-2016 15:23:17
Uptime 0 days 0 hr. 2 min. 33 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/product/12.1.0/dbhome_2/network/admin/listener.ora
Listener Log File /u01/app/oracle/diag/tnslsnr/soa-training/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=localhost)(PORT=5501))(Security=(my_wallet_directory=/u01/app/oracle/admin/ustore/xdb_wallet))(Presentation=HTTP)(Session=RAW))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=localhost)(PORT=5500))(Security=(my_wallet_directory=/u01/app/oracle/product/12.1.0/dbhome_2/admin/soadb/xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "soadb.oracle.com" has 1 instance(s).
Instance "soadb", status READY, has 1 handler(s) for this service...
Service "soadbXDB.oracle.com" has 1 instance(s).
Instance "soadb", status READY, has 1 handler(s) for this service...
Service "ustore" has 1 instance(s).
Instance "ustore", status READY, has 1 handler(s) for this service...
Service "ustoreXDB" has 1 instance(s).
Instance "ustore", status READY, has 1 handler(s) for this service...
The command completed successfully
The problem is in the domain:
Your tnsalias: (SERVICE_NAME = soadb)
Your listener: Service "soadb.oracle.com" has 1 instance(s).
Change your tns entry as follows:
SOADB =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = soadb.oracle.com)
)
)
(ZD9396)