Someone please help me. im using icehouse legacy network,i have an issue when creating /16 network.

nova network-create service-net --bridge br200 --multi-host T \
--fixed-range-v4 10.50.0.0/16

ERROR: The server has either erred or is incapable of performing the requested operation. (HTTP 500) (Request-ID: req-73c121bd-8be2-448b-bbcd-d5d8aa778291)

2014-09-26 17:44:23.955 9116 ERROR nova.servicegroup.drivers.db [-] Recovered model server connection!
2014-09-26 17:44:23.956 9116 WARNING nova.openstack.common.loopingcall [-] task run outlasted interval by 33.789621 sec
2014-09-26 17:44:23.970 9116 WARNING oslo.messaging._drivers.amqpdriver [-] No calling threads waiting for msg_id : 28dae932d4d24ba9a2222afa2c1a87a2, message : {u'_unique_id': u'a5d15c41314f4187bed1aeabaca6e85b', u'failure': None, u'result': None, u'ending': True}
2014-09-26 17:44:23.971 9116 WARNING oslo.messaging._drivers.amqpdriver [-] _queues: '0c1838c4e651476c9ed0284c58e3d925': Queue at 0x33cd910 maxsize=None>

but when im using /24 subnet everything works fine.

nova network-create service-net --bridge br200 --multi-host T \
--fixed-range-v4 10.50.0.0/24

root@controller:~# nova net-list
+--------------------------------------+----------------+----------------+
| ID                                   | Label          | CIDR           |
+--------------------------------------+----------------+----------------+
| aded2b05-3465-4430-8552-95223196b5da | service-net    | 10.50.0.0/24   |
+--------------------------------------+----------------+----------------+

COMPUTE NODE

cat /etc/nova/nova.conf

[DEFAULT]
dhcpbridge_flagfile=/etc/nova/nova.conf
dhcpbridge=/usr/bin/nova-dhcpbridge
logdir=/var/log/nova
state_path=/var/lib/nova
lock_path=/var/lock/nova
force_dhcp_release=True
iscsi_helper=tgtadm
libvirt_use_virtio_for_bridges=True
connection_type=libvirt
root_helper=sudo nova-rootwrap /etc/nova/rootwrap.conf
verbose=True
ec2_private_dns_show_ip=True
api_paste_config=/etc/nova/api-paste.ini
volumes_path=/var/lib/nova/volumes
enabled_apis=ec2,osapi_compute,metadata

auth_strategy = keystone
rpc_backend = rabbit 
rabbit_host = controller
rabbit_password = xxxxx
my_ip = 10.50.0.6
vnc_enabled = True
vncserver_listen = 0.0.0.0
vncserver_proxyclient_address = 10.50.0.6
novncproxy_base_url = http://controller:6080/vnc_auto.html
glance_host = controller

network_api_class = nova.network.api.API
security_group_api = nova
firewall_driver = nova.virt.libvirt.firewall.IptablesFirewallDriver
network_manager = nova.network.manager.FlatManager
network_size = 256
allow_same_net_traffic = False
multi_host = True
send_arp_for_ha = True
share_dhcp_address = True
force_dhcp_release = True
flat_network_bridge = br200
flat_interface = eth0
public_interface = eth0
flat_injected=True

[database]
connection = mysql://nova:xxxxx@controller/nova

[keystone_authtoken]
auth_uri = http://controller:5000
auth_host = controller
auth_port = 35357
auth_protocol = http
admin_tenant_name = service
admin_user = nova 
admin_password = xxxxx

Thank you in advance