diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 697c7854b7..494caff068 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -13521,7 +13521,7 @@ receive_secure_serial(isc_task_t *task, isc_event_t *event) {
 	ZONEDB_UNLOCK(&zone->dblock, isc_rwlocktype_read);
 
 	if (zone->raw != NULL)
-                dns_zone_attach(zone->raw, &raw);
+		dns_zone_attach(zone->raw, &raw);
 	UNLOCK_ZONE(zone);
 
 	/*