ORA-16191: Primary log shipping client not logged on standby

Reasons: 
Primary and standby database SYS password is not same and it creates conflicts to access the standby database and vice versa.

Solution:

Step-1:  Check error and remote_login_passwordfile parameter

SQL> SELECT DESTINATION, STATUS, ERROR FROM V$ARCHIVE_DEST WHERE DEST_ID=2;

DESTINATION
--------------------------------------------------------------------------------
STATUS    ERROR
--------- -----------------------------------------------------------------
dcstdb
ERROR     ORA-16191: Primary log shipping client not logged on standby


SQL> show parameter remote_login_passwordfile;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
remote_login_passwordfile            string      EXCLUSIVE
SQL>


Step-2: Disable log_archive_dest_state_2

SQL> show parameter log_archive_dest_state_2;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_state_2             string      ENABLE
log_archive_dest_state_20            string      enable
log_archive_dest_state_21            string      enable
log_archive_dest_state_22            string      enable
log_archive_dest_state_23            string      enable
log_archive_dest_state_24            string      enable
log_archive_dest_state_25            string      enable
log_archive_dest_state_26            string      enable
log_archive_dest_state_27            string      enable
log_archive_dest_state_28            string      enable
log_archive_dest_state_29            string      enable

SQL>
SQL> alter system set log_archive_dest_state_2=DEFER sid='*' scope=both;

System altered.

SQL> show parameter log_archive_dest_state_2;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_state_2             string      DEFER
log_archive_dest_state_20            string      enable
log_archive_dest_state_21            string      enable
log_archive_dest_state_22            string      enable
log_archive_dest_state_23            string      enable
log_archive_dest_state_24            string      enable
log_archive_dest_state_25            string      enable
log_archive_dest_state_26            string      enable
log_archive_dest_state_27            string      enable
log_archive_dest_state_28            string      enable
log_archive_dest_state_29            string      enable
SQL> 


Step-3: Re-Create password file by following command

oracle@testbk [/u02/app/oracle/product/11.2.0.4/dbhome_1/dbs]$orapwd FILE=orapw$ORACLE_SID ENTRIES=30 ignorecase=Y
Enter password for SYS:


Step-4: Shutdown Standby Server

oracle@dcstdb [/u02/app/oracle/product/11.2.0.4/dbhome_1/dbs]$sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Tue May 3 16:43:01 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.


Step-5: Transfer Primary DB password file to Standby server
oracle@testbk [/u02/app/oracle/product/11.2.0.4/dbhome_1/dbs]$scp orapwtestbk1 oracle@dcstdb:/u02/app/oracle/product/11.2.0.4/dbhome_1/dbs/orapwdcstdb1                                
Password:
orapwtestbk1                                                          100% 6144     6.0KB/s   6.0KB/s   00:00


Step-6: Startup Standby Server

SQL> startup
ORACLE instance started.

Total System Global Area 5127602176 bytes
Fixed Size                  2214432 bytes
Variable Size            4580181472 bytes
Database Buffers          536870912 bytes
Redo Buffers                8335360 bytes
Database mounted.
Database opened.
SQL>

Step-7: recovery process start

SQL> alter database reocver managed standby database using current logfile disconnect from session;


Step-8: Enable log_archive_dest_state_2 of PRIMARY.

SQL> alter system set log_archive_dest_state_2=ENABLE sid='*' scope=both;
SQL> alter system switch all logfile;

SQL> SELECT DESTINATION, STATUS, ERROR FROM V$ARCHIVE_DEST WHERE DEST_ID=2;

DESTINATION
--------------------------------------------------------------------------------
STATUS    ERROR
--------- -----------------------------------------------------------------
dcstdb
VALID