Ceph ISCSI Gateway

Hi
while adding hosts in host-groups in gwcli i get the below error . The ceph version is 3 and i have 2 iscsi gateway nodes .

/iscsi-target...s/mgmt-oc-eaa> host add iqn.1994-05.com.redhat:mgmt3-oc-eaa
Failed :hostgroup create/update failed on dn18-ceph-eaa. Group request failed validation
/iscsi-target...s/mgmt-oc-eaa>

Thanks/Regards
Sadiq