From the log I saw
[----] I, [2018-10-17T13:04:20.573829 #1824:ee3130] INFO -- : Q-task_id([service_template_provision_task_8]) MIQ(MiqEvent#process_evm_event) target = [#<ServiceOrchestration id: 6, name: "CFN EC2 -20181017-130409", description: "", guid: "f1e57fc9-4384-434e-9ec7-52a5a40ea268", type: "ServiceOrchestration", service_template_id: 1, options: {:dialog=>{"dialog_vm_name"=>"sample1"}, :orchestration_stack=>{:name=>nil}, :create_options=>{}}, display: true, created_at: "2018-10-17 17:04:02", updated_at: "2018-10-17 17:04:17", evm_owner_id: 1, miq_group_id: 2, retired: false, retires_on: nil, retirement_warn: nil, retirement_last_warn: nil, retirement_state: nil, retirement_requester: nil, tenant_id: 1, ancestry: nil, initiator: "user">]
The orchestration stack has no name, no create_options. There is no way to actually provision your stack. Did you use a correct dialog that provides a proper name and parameters required by the template?