private AuthConfig getAuthConfigFromSettings(Settings settings, String user, String registry) throws MojoExecutionException {
        Server defaultServer = null;
        Server found;
        for (Server server : settings.getServers()) {
            String id = server.getId();

            // Remember a default server without user as fallback for later
            if (defaultServer == null) {
                defaultServer = checkForServer(server, id, registry, null);
            }
            // Check for specific server with user part
            found = checkForServer(server, id, registry, user);
            if (found != null) {
                return createAuthConfigFromServer(found);
            }
        }
        return defaultServer != null ? createAuthConfigFromServer(defaultServer) : 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