As explained in the upstream bug https://bugs.launchpad.net/bugs/1592988 listing domains is privileged operation in the default RBAC policy causing:
"You are not authorized to perform the requested action: identity:list_domains"
Nathan, per your comment #5, does that issue still exist for us to document in OSP 8,9,10, and/or 13? Looking to get this closed properly and we'll make the changes in those releases if it is still applicable there. But OSP 7 is EOL.