ORA-00234,ORA-17503,ORA-15045

RMAN> SHOW SNAPSHOT CONTROLFILE NAME; 

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of show command at 09/07/2016 08:41:04
RMAN-03014: implicit resync of recovery catalog failed
RMAN-03009: failure of full resync command on default channel at 09/07/2016 08:41:04
ORA-00234: error in identifying or opening snapshot or copy control file
ORA-00202: control file: '+DB4_ORADATA'
ORA-17503: ksfdopn:2 Failed to open file +DB4_ORADATA
ORA-15045: ASM file name '+DB4_ORADATA' is not in reference form

Everything I run on the catalog database gives me the above error

Solution :

Make the change as sys user

SQL> EXECUTE SYS.DBMS_BACKUP_RESTORE.CFILESETSNAPSHOTNAME ('+DB4_ORADATA/snapcf_db4.f');

PL/SQL procedure successfully completed.

this resolved the rman issue..