'#description'=>t('The parent domain hostname to use as the canonical hostname of this microsite. The parent domain must not itself be a domain microsite.'),
$form_state->setErrorByName('domain_microsite_is_domain_microsite',t('This domain may not be a domain microsite because other domain microsites have specified it as a parent domain. Form must be reloaded to see new options.'));
$form_state->setErrorByName('domain_microsite_is_domain_microsite',t('This domain may not be a domain microsite because other domain microsites have specified it as a parent domain.'));