You can get ORA-01110 ORA-01111 UNNAMED error in you dataguard after adding new datafile to the primary database.
If standby_file_management parameter is manual in your dataguard environment then you can take this error.
You can solve this problem with below steps.
1. Cancel dataguard MRP process.
alter database recover managed standby database cancel;
2. You need to change your datafile name with below command. This UNNAMED00324 name will be in dataguard alertlog so check the alertlog and define right UNNAMED file name and path.
ALTER DATABASE CREATE DATAFILE '/u01/app/oracle/product/18.104.22.168/dbhome_1/dbs/UNNAMED00324' AS '+DATAC1';
3.If you change datafile name with above command then you can start dataguard MRP process like below.
alter database recover managed standby database disconnect from session;
If you don’t want to see this error again, you can change the standby_file_management parameter like below.
alter system set standby_file_management='AUTO' scope=both;