[Users] could not add iscsi disk in ovirt.

Hi guys, I am running ovirt with NFS as storage pool. Everything is working quite fine for me. The only problem is I could not add the a new iscsi disk in Disk tab. When I go to the Disk tab there is an option of adding new disk from internal storage and another option is add External (Direct Lun). When I opt for the External (Direct LUN), I am able to discover the Lun but could not log in to that lun using the ovirt web console. Whereas when I try to login to that lun using the isciadm in command line I am able to login. Any help??