STANDBY_FILE_MANAGEMENT parameter is not configured Auto

If you have not set standby_file_management to Auto on the primary  and you add a datafile to the primary  you will see the following in the alert log of the standby

File #9 added to control file as ‘UNNAMED00009’ because
the parameter STANDBY_FILE_MANAGEMENT is set to MANUAL
The file should be manually created to continue.
MRP0: Background Media Recovery terminated with error 1274

This will stop you standby database from being in recovery mode until this is fixed , so if you are using OMF do the following to fix it

alter database create datafile ‘/u01/app/oracloud/product/12.1.0/db_1/dbs/UNNAMED00009’ as new

also change the following parameters using dataguard broker

edit database clouddr set property StandbyFileManagement=AUTO;

edit database cloud set property StandbyFileManagement=AUTO;

then restart the dataguard broker