Review the autoscaler error message
Check your logs for a message similar to:

    Kubernetes Autoscaler, Deadlock for Pod: '{pod-name}' 
    Can't scale up an Instance since PersistentVolumeClaim: 
    '{PVC-name}' 
    VolumeId: '{vol-name}' is already attached to an existing Instance: 
    '{instance-ID}' Please consider using a new PersistentVolumeClaim or open a 
   support ticket.

Confirm that the volume is attached to another node
Look at the persistent volume details and verify that the volume is currently attached to another instance. The pod cannot use this volume until it’s available.

Free up space on the node that holds the volume
If the current node has no remaining capacity for the pod, adjust workloads or free resources so the pod can run on that node and use the volume it already claimed.

Verify that the pod can run on the node
After freeing space, confirm that the pod’s resource requests match the node’s available capacity.