keystoneauth1.exceptions.catalog.EndpointNotFound: public endpoint for maintenance service not found

Question

After successfully installing openstack, keystone and tacker, I tried to create VNF instance by using this command:

tacker vnf-create --vnfd-name myVNF_vnfd myVNF_vnf

Checking the result:

$ openstack vnf list
+--------------------------------------+-------------------------+---------------------- -+--------+--------------------------------------+-------------------------------------- +
| ID                                   | Name                    | Mgmt Ip Address       | Status | VIM ID                               | VNFD ID                              |
+--------------------------------------+-------------------------+---------------------- -+--------+--------------------------------------+-------------------------------------- +
| 07745879-0bd8-4e7d-93c4-0d7deacf1a69 | myVNF_vnf | {"VDU1": "10.0.0.39"} | ACTIVE | 0f4916bb-cade-41b7-b644-185aad5593fe | c3dfa45a-ed62-47b9-b849-26d6d653cb67 |
+--------------------------------------+-------------------------+-----------------------+--------+--------------------------------------+--------------------------------------+

Therefore, I know that the vnf instance has successfully deployed but there is an error on tacker server:

Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/eventlet/greenpool.py", line 88, in _spawn_n_impl
func(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/tacker/vnfm/plugin.py", line 456, in create_vnf_wait
self.config_vnf(context, vnf_dict)
File "/usr/local/lib/python3.6/dist-packages/tacker/vnfm/plugin.py", line 302, in config_vnf
vnf_dict)
File "/usr/local/lib/python3.6/dist-packages/tacker/common/log.py", line 35, in wrapper
return method(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/tacker/plugins/fenix.py", line 88, in create_vnf_constraints
'project_instance'])
File "/usr/local/lib/python3.6/dist-packages/tacker/common/log.py", line 35, in wrapper
return method(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/tacker/plugins/fenix.py", line 112, in update_vnf_constraints
data_func='%s_%s' % (action, obj))
File "/usr/local/lib/python3.6/dist-packages/tacker/common/log.py", line 35, in wrapper
return method(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/tacker/plugins/fenix.py", line 81, in request
self._request(plugin, context, vnf_dict, params, method, is_reply)
File "/usr/local/lib/python3.6/dist-packages/tacker/common/log.py", line 35, in wrapper
return method(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/tacker/plugins/fenix.py", line 149, in _request
service_type='maintenance', region_name=client.region_name)
File "/usr/local/lib/python3.6/dist-packages/keystoneauth1/session.py", line 1243, in get_endpoint
return auth.get_endpoint(self, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/keystoneauth1/identity/base.py", line 380, in get_endpoint
allow_version_hack=allow_version_hack, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/keystoneauth1/identity/base.py", line 279, in get_endpoint_data
service_name=service_name)
File "/usr/local/lib/python3.6/dist-packages/keystoneauth1/access/service_catalog.py", line 462, in endpoint_data_for
raise exceptions.EndpointNotFound(msg)
keystoneauth1.exceptions.catalog.EndpointNotFound: public endpoint for maintenance service not found

I do not understand what is maintenance service or what I missed for the installation. Please help me. Thank you in advance.