A worker machine failed to get provisioned (Failed Phase). 
$ oc describe machine ostest-6f5qn-worker-0-sm8sw -n openshift-machine-api
Name:         ostest-6f5qn-worker-0-sm8sw
Namespace:    openshift-machine-api
Labels:       machine.openshift.io/cluster-api-cluster=ostest-6f5qn
              machine.openshift.io/cluster-api-machine-role=worker
              machine.openshift.io/cluster-api-machine-type=worker
              machine.openshift.io/cluster-api-machineset=ostest-6f5qn-worker-0
Annotations:  machine.openshift.io/instance-state: Unknown
API Version:  machine.openshift.io/v1beta1
Kind:         Machine
Metadata:
  Creation Timestamp:  2024-03-04T09:19:23Z
  Finalizers:
    machine.machine.openshift.io
  Generate Name:  ostest-6f5qn-worker-0-
  Generation:     1
  Owner References:
    API Version:           machine.openshift.io/v1beta1
    Block Owner Deletion:  true
    Controller:            true
    Kind:                  MachineSet
    Name:                  ostest-6f5qn-worker-0
    UID:                   e25be560-94f5-42c5-a843-b87c2e18485d
  Resource Version:        19713
  UID:                     800fbcd5-d6f9-4c16-b095-82d524cf422e
Spec:
  Lifecycle Hooks:
  Metadata:
  Provider Spec:
    Value:
      API Version:  machine.openshift.io/v1alpha1
      Cloud Name:   openstack
      Clouds Secret:
        Name:       openstack-cloud-credentials
        Namespace:  openshift-machine-api
      Flavor:       worker
      Image:        ostest-6f5qn-rhcos
      Kind:         OpenstackProviderSpec
      Metadata:
        Creation Timestamp:  <nil>
      Networks:
        Filter:
          Id:  63c1d056-e896-48bc-9342-87f39d67770a
        Subnets:
          Filter:
            Name:  subnet-dualstack-v4
          Filter:
            Name:  subnet-dualstack-v6
        Filter:
        No Allowed Address Pairs:  true
        Uuid:                      c4672bc4-0fb3-4057-b716-56db58f9be0e
      Security Groups:
        Filter:
        Name:             ostest-6f5qn-worker
      Server Group Name:  ostest-6f5qn-worker
      Server Metadata:
        Name:                  ostest-6f5qn-worker
        Openshift Cluster ID:  ostest-6f5qn
      Tags:
        openshiftClusterID=ostest-6f5qn
      Trunk:  true
      User Data Secret:
        Name:  worker-user-data
Status:
  Conditions:
    Last Transition Time:  2024-03-04T09:19:51Z
    Status:                True
    Type:                  Drainable
    Last Transition Time:  2024-03-04T09:19:51Z
    Message:               Instance has not been created
    Reason:                InstanceNotCreated
    Severity:              Warning
    Status:                False
    Type:                  InstanceExists
    Last Transition Time:  2024-03-04T09:19:51Z
    Status:                True
    Type:                  Terminable
  Error Message:           Machine validation failed: 
Error getting a new instance service from the machine: Failed to get cloud from secret: Failed to get secrets from kubernetes api: Get "https://172.30.0.1:443/api/v1/namespaces/openshift-machine-api/secrets/openstack-cloud-credentials": http2: client connection lost
  Error Reason:  InvalidConfiguration
  Last Updated:  2024-03-04T09:23:43Z
  Phase:         Failed
Events:          <none>

When deleted the machine a new one was created successfully

    4.15.0

    1.
    2.
    3.
    

 I'd expect in case of a temporary failure that the machine will be deleted and recreated automatically