private Server checkForServer(Server server, String id, String registry, String user) {

        String[] registries = registry != null ? new String[] { registry } : DEFAULT_REGISTRIES;
        for (String reg : registries) {
            if (id.equals(user == null ? reg : reg + "/" + user)) {
                return server;
            }
        }
        return null;
    }
Try using the AWS credentials provided via ENV variables.
See https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-envvars.html
src/main/java/io/fabric8/maven/docker/util/AuthConfigFactory.java