Since version 1.9.8.2.10 DMS uses external worker container to create previews and parse emails. To deploy it correctly in existing environments, deploy_script must be updated to the latest master and next lines must be added to commands.conf. Please use the latest image version that is available at the moment of deployment.
commands.conf
# Settings of WORKER container WORKER_IMAGE_VERSION="1.1-rc" WORKER_IMAGE_NAME="paceip/dms_worker" WORKER_CONTAINER_NAME="worker"