diff --git a/dnsapi/dns_dgon.sh b/dnsapi/dns_dgon.sh
index 24e1a9f2..c176afd3 100755
--- a/dnsapi/dns_dgon.sh
+++ b/dnsapi/dns_dgon.sh
@@ -178,7 +178,7 @@ dns_dgon_rm() {
 ## _domain="domain.com"
 _get_base_domain() {
   # args
-  fulldomain="$(echo "$1" | tr '[:upper:]' '[:lower:]')"
+  fulldomain="$(echo "$1" | _lower_case)"
   _debug fulldomain "$fulldomain"
 
   # domain max legal length = 253