RMAN fails to backup Snapshot controlfile in RAC on shared location

I have Oracle19.9.0 RAC on Oracle Linux Server 7.9. For RMAN backup I am using EMC's Data Domain storage which is NFS mounted on all the DB nodes of the RAC.

For NFS mount I am using these options : rw,bg,hard,nolock,nfsvers=3,tcp,noac,rsize=1048600,wsize=1048600

I am trying to follow "In RAC environment from 11.2 onwards Backup Or Snapshot controlfile needs to be in shared location (Doc ID 1472171.1)"

This is how I have configured AUTOBACKUP CONTROLFILE and SNAPSHOT CONTROLFILE :

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO './%d/AUTO.ctl';

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/