Dataguard on Oracle RAC

Hi,

I need your help to solve my error which I am facing while configuring dataguard on Oralce RAC , my db version is 12c 12.1.0.2

My problem :

===> I am not able to connect to my standby db from primary database using tns net service name, it's showing me error invalid username/password.

          I am getting tnsping OK.

Below are the steps which I have performed to configure my datagaurd.

Step 1: modified dataguard related parameter.

alter system set LOG_ARCHIVE_CONFIG='DG_CONFIG=(DG,STD)' scope=both sid='*';

alter system set LOG_ARCHIVE_DEST_1='LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=DG' scope=both sid='*';