If a domain zone file was edited manually or changes were not saved in HSPcomplete database, it is possible to restore its configuration to the one that was saved in the HSPcomplete database before. In this case, you can either use a default DNS template or just restore a zone file from the database.
To use a default DNS template for zone files restoring, set this in Domain Manager - Setup.
To restore a domain zone file, go to the Service Director - Domain Manager - Domains, select a domain and click the Restore DNS Zone from DB button.