def get_authorizations(self, acme_client, order, order_info):
        """ The list can be empty if all hostname validations are still valid"""
        authorizations = []

        for domain in order_info.domains:

            # If CNAME exists, set host to the target address
            target_domain = domain
            if current_app.config.get("ACME_ENABLE_DELEGATED_CNAME", False):
                cname_result, _ = self.strip_wildcard(domain)
                cname_result = challenges.DNS01().validation_domain_name(cname_result)
                cname_result = self.get_cname(cname_result)
                if cname_result:
                    target_domain = cname_result
                    self.autodetect_dns_providers(target_domain)
                    metrics.send(
                        "get_authorizations_cname_delegation_for_domain", "counter", 1, metric_tags={"domain": domain}
                    )

            if not self.dns_providers_for_domain.get(target_domain):
                metrics.send(
                    "get_authorizations_no_dns_provider_for_domain", "counter", 1
                )
                raise Exception(f"No DNS providers found for domain: {target_domain}")

            for dns_provider in self.dns_providers_for_domain[target_domain]:
                dns_provider_plugin = self.get_dns_provider(dns_provider.provider_type)
                dns_provider_options = json.loads(dns_provider.credentials)
                account_number = dns_provider_options.get("account_id")
                authz_record = self.start_dns_challenge(
                    acme_client,
                    account_number,
                    domain,
                    target_domain,
                    dns_provider_plugin,
                    order,
                    dns_provider.options,
                )
                # it can be null, if hostname is still valid
                if authz_record:
                    authorizations.append(authz_record)
        return authorizations
 The list can be empty if all hostname validations are still valid
lemur/plugins/lemur_acme/acme_handlers.py