OpenShift on Azure installation ends with 'FATAL failed to initialize the cluster'

Issue

OpenShift 4.x installation in Azure cloud environment fails. The error at the end of the .openshift-install.log states:

FATAL failed to initialize the cluster: Some cluster operators are still updating: authentication, console, image-registry, ingress, monitoring

Logs from the machineconfig-api-controller:

318 13:36:38.868864 1 controller.go:321] Failed to create machine "apps-worker-region": failed to reconcile machine "apps-worker-region": compute.VirtualMachinesClient#CreateOrUpdate: Failure sending request: StatusCode=400 -- Original Error: Code="InvalidAvailabilityZone" Message="The zone(s) '1' for resource 'Microsoft.Compute/virtualMachines/apps-worker-region' is not supported. The supported zones for location 'region' are ''"
I0318 13:36:42.414561 1 controller.go:376] Machine "apps-worker-region" in namespace "openshift-machine-api" doesn't specify "cluster.k8s.io/cluster-name" label, assuming nil cluster  
W0318 13:36:42.414593 1 controller.go:273] Machine "apps-worker-region" has gone "Failed" phase. It won't reconcile