This problem was reported by one of our customer, but it looks like it affects all RHOSP 17.1 operators with ML2/OVN: v2.0/address-groups endpoint returns

ResourceNotFound: 404: Client Error for url: http://10.0.0.141:9696/v2.0/address-groups, The resource could not be found.

From the code it looks like this situation is caused by missing patch https://review.opendev.org/c/openstack/neutron/+/765299 , but I am not sure if it is simply about this patch, or OVN in RHOSP 17.1 is not ready for address groups as well.