Hypervisor list empty

Hi! I just deploy an Openstack Xena. Everything was fine, till I wanted to deploy one instance. -> openstack compute service list (output)

| 11 | nova-compute | Node01.maas | nova | enabled | up | 2022-05-08T13:31:27.000000 | | 12 | nova-compute | Node03.maas | nova | enabled | up | 2022-05-08T13:31:30.000000 | | 13 | nova-compute | Node04.maas | nova | enabled | up | 2022-05-08T13:31:31.000000 | | 14 | nova-compute | Node02.maas | nova | enabled | up | 2022-05-08T13:31:30.000000 |

But when I check the hypervisor list, the list is empty(openstack hypervisor list) Also when I try to deploy one instance, it gave me the error message’: 'No valid host was found. So the computer service is enabled, but there is no hypervisor. Also, if I try to disable one of the compute nodes, I get this: Compute service nova-compute of host Node02.maas failed to set.