resyncing from database with DB_UNIQUE_NAME RMAN-03014: implicit resync of recovery catalog failed

There has been a structural changes on the primary DB ( like adding of data files,etc) and during the time, tried to connect from standby database using rman as below

rman target / catalog rman/rman@dbcat

Recovery Manager: Release 11.2.0.4.0 - Production on Mon Oct 21 13:30:38 2019

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: SPROD (DBID=1981104798)
connected to recovery catalog database


RMAN> show all;

2> ;

ORA-20079: full resync from primary database is not done

doing automatic resync from primary
resyncing from database with DB_UNIQUE_NAME SPROD
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of show command at 10/21/2019 11:00:29
RMAN-03014: implicit resync of recovery catalog failed
RMAN-03009: failure of partial resync command on default channel at 10/21/2019 11:00:29
ORA-17629: Cannot connect to the remote database server
ORA-17627: ORA-01017: invalid username/password; logon denied

ORA-17629: Cannot connect to the remote database server

rman tries to resync the standby from primary using db_unique_name.

However, RMAN is unable to connect to the primary because no connect string was used when connecting to the standby - 

in order to resync from another host in a Data Guard configuration , the connection to target must be made with a username, password and alias.  

This is documentation Bug 13774434: ORA-17629, ORA-17628 DURING RESYNC CATALOG FROM DB_UNIQUE_NAME ALL;

SoLUTION

Use a TNS connect string when connecting to the standby eg

rman target sys/sys123@primary_db catalog rman/rman@dbcat


RMAN> show all;

RMAN configuration parameters for database with db_unique_name SPRODSMU are:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 2 DAYS;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK;

CONFIGURE CONTROLFILE AUTOBACKUP ON;