ORA-12514: TNS:listener does not currently know of service requested in connect descriptor at Dataguard Switchover

This is most likely because the special service db_unique_name_DGMGRL has not been registered properly with the listener.

This is one of the requirements when configuring Data Guard broker.

From Oracle Docs :

To enable DGMGRL to restart instances during the course of broker operations, a service with a specific name must be statically registered with the local listener of each instance. The value for the GLOBAL_DBNAME attribute must be set to a concatenation of db_unique_name_DGMGRL.db_domain.

sys@ PRIMARY> show parameter db_uniqu
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      primary

sys@ SECONDARY> show parameter db_unique
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      secondary

Updated Listener.ora  : I had to add GLOBAL_DBNAME for both databases

SID_LIST_LISTENER =
 (SID_LIST =
 (SID_DESC =
 (SID_NAME = primary)
 (ORACLE_HOME = C:\app\patilsa\product\11.2.0\dbhome_1)
 (GLOBAL_DBNAME = primary_DGMGRL)
 )
 (SID_DESC =
 (SID_NAME = secondary)
 (ORACLE_HOME = C:\app\patilsa\product\11.2.0\dbhome_1)
 (GLOBAL_DBNAME = secondary_DGMGRL)
 )
 )