diff --git a/dnsapi/dns_namecom.sh b/dnsapi/dns_namecom.sh
index 2d3293c8..667f7688 100755
--- a/dnsapi/dns_namecom.sh
+++ b/dnsapi/dns_namecom.sh
@@ -30,7 +30,7 @@ _saveaccountconf Namecom_Token "$Namecom_Token"
 # Auth string
 # Name.com API v4 uses http basic auth to authenticate
 # need to convert the token for http auth
-_namecom_auth=$(printf "$Namecom_Username:$Namecom_Token" | base64)
+_namecom_auth=$(printf "%s:%s" "$Namecom_Username" "$Namecom_Token" | base64)
 
 #Usage: dns_namecom_add   _acme-challenge.www.domain.com   "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
 dns_namecom_add() {