Oracle Message ORA-15003 - diskgroup string already mounted in another lock name space

ERRORdiskgroup string already mounted in another lock name space
CAUSEThe diskgroup could not be mounted by the ASM instance because it was operating in a lockspace different than another existing ASM instance which had already mounted the diskgroup.
ACTIONCheck the LOCK_NAME_SPACE initialization parameter value, or dismount the diskgroup from the other ASM instances.