Elastic Search Docker unauthorised master failure

Job #182682599 failed for 37e74079:

Happening on non-master branches too

Starting service docker.elastic.co/elasticsearch/elasticsearch:5.6.12 ...
Pulling docker image docker.elastic.co/elasticsearch/elasticsearch:5.6.12 ...
ERROR: Preparation failed: Error response from daemon: unauthorized: authentication required (executor_docker.go:168:0s)