I'm having this issue too (and also a colleague) in the eastus region:

run failed with error message
 Cluster '1212-135649-a2x5p6jg' was terminated. Reason: BOOTSTRAP_TIMEOUT (SERVICE_FAULT). Parameters: databricks_error_message:Bootstrap Timeout. Please try again later.
Instance bootstrap inferred timeout reason: UnknownReason
Failure message: Bootstrap script took too long and timeout. 
VM extension code: ProvisioningState/succeeded
instanceId: InstanceId(022733c3085c4460ade4fa8042d12c85)
workerEnv: workerenv-6505902102920425
Additional details (may be truncated):