Error creating container: 400 Client Error: Bad Request ("invalid reference format")

[christia...@itsv.at]

while trying to build image for linux ppc64le the following comes up.

TASK [image_build : Build sdist builder image] ****************************************************************************************************************************************************************
changed: [localhost -> localhost]

TASK [image_build : Build AWX distribution using container] ***************************************************************************************************************************************************
fatal: [localhost -> localhost]: FAILED! => {"changed": false, "msg": "Error creating container: 400 Client Error: Bad Request (\"invalid reference format\")"}
 to retry, use: --limit @/root/awx/installer/install.retry

how can i see what really happens in the background, any verbose docker 
locks
that i a can loock at? the message itself is somewhat useless to me. i 
already set ansible to verbose but this also was of no help.

builder image is built ok imho




REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
awx_sdist_builder   latest              d269ef0b39d5        7 minutes ago       703MB
ppc64le/centos      7                   3c3bccc9acb8        5 weeks ago         282MB

AWX version: 1.0.6-339-g07ddfe2
AWX install method: docker on linux
Ansible version: 2.6
Operating System: RedHat 7.4 ppc64le
Web Browser: Firefox