Overcloud deploy fails with The WebSocket timed out before the Workflow completed.

Issue

• Overcloud deploy fails with The WebSocket timed out before the Workflow completed.

(undercloud) [stack@director ~]$ ./overcloud-deploy.sh 
mié oct  3 10:03:46 EDT 2018
Started Mistral Workflow tripleo.validations.v1.check_pre_deployment_validations. Execution ID: 0f292060-d4b8-4fee-9030-786c7663a465
Waiting for messages on queue 'tripleo' with no timeout.
Removing the current plan files
Uploading new plan files
Started Mistral Workflow tripleo.plan_management.v1.update_deployment_plan. Execution ID: da570b38-cc6d-4138-abcb-14e245b03ca8
Timed out waiting for messages from Execution (ID: da570b38-cc6d-4138-abcb-14e245b03ca8, State: RUNNING). The WebSocket timed out before the Workflow completed.

undercloud) [stack@director overcloud-validation]$ openstack orchestration template validate --show-nested --template ~/overcloud-validation/overcloud.yaml -e ~/overcloud-validation/overcloud-resource-registry-puppet.yaml -e /home/stack/templates/node-info.yaml -e /home/stack/templates/network-isolation.yaml -e /home/stack/templates/CeilometerStoreEvents.yaml -e /home/stack/templates/TimeZone.yaml -e /home/stack/templates/network-environment.yaml -e /home/stack/templates/enable-tls.yaml -e /home/stack/templates/cloudname.yaml -e /home/stack/templates/inject-trust-anchor.yaml 
ERROR: Internal Error