Can't create Google Cloud TPU: an internal error has occurred code 13

I can't create a Google Cloud TPU:

gcloud compute tpus create bert-tpu --version=1.15 --preemptible --zone=europe-west4-a
Create request issued for: [bert-tpu]
Waiting for operation [projects/<x>/locations/europe-west4-a/operations/<xx>] to complete...failed.
ERROR: (gcloud.compute.tpus.create) {
  "code": 13,
  "message": "an internal error has occurred"
}

Web GUI Console: same result:

Creating TPU node "bert-tpu" failed
Error: an internal error has occurred

I've tried all combinations of preemptible and non-preemptible, tensorflow version 1.11 and 1.15, and v2-8 and v3-8.

I wasn't any to find any reports of this problem via google search. Has anyone else encountered/solved this problem?