sys username and password invalid

 SYS USERNAME and PASSWORD INVALID:

check select * from v$pwfile_users;

it should give value for sys user if not create password file in $ORACLE_HOME/dbs

cd  <ORACLE_HOME>/dbs

CREATE PASSWORD FILE

$ORACLE_HOME/bin/orapwd file=<OH>/dbs/orapw<sid> password=<password> entries=<max entries number>;

Using the sys user and the password which is set in the password file to logging into the dbconsole

Make sure the DB parameter REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE

SQL> show parameter REMOTE_LOGIN_PASSWORDFILE

NAME                                   TYPE     VALUE
------------------------------------ -----------  ------------------------------
remote_login_passwordfile       string       EXCLUSIVE

check    sqlnet.ora below enters: 

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

# Generated by Oracle configuration tools.

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

SQLNET.EXPIRE_TIME=10

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

SQLNET.ALLOWED_LOGON_VERSION_SERVER=8

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=8

now login with sys user it should login.