diff --git a/gen-cert.sh b/gen-cert.sh
index 52f5f8d..84c95f3 100755
--- a/gen-cert.sh
+++ b/gen-cert.sh
@@ -27,7 +27,7 @@ PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 #	Original proxy idea from:
 #	http://evolvedigital.co.uk/how-to-get-letsencrypt-working-with-ispconfig-3/
 
-PROXYAUTH="--standalone --standalone-supported-challenges http-01 --http-01-port 9999"
+PROXYAUTH="--standalone --preferred-challenges http-01 --http-01-port 9999"
 
 # Location of LetsEncrypt binary we use.  Leave unset if you want to let it find automatically
 #LEBINARY="/usr/src/letsencrypt/certbot-auto"
diff --git a/gen-unifi-cert.sh b/gen-unifi-cert.sh
index c358d84..51c45a8 100755
--- a/gen-unifi-cert.sh
+++ b/gen-unifi-cert.sh
@@ -86,7 +86,7 @@ if [[ ${onlyinsert} != "yes" ]]; then
 	${LEBINARY} \
 		--server https://acme-v01.api.letsencrypt.org/directory \
     	--agree-tos \
-		--standalone --standalone-supported-challenges tls-sni-01 \
+		--standalone --preferred-challenges tls-sni-01 \
     	${LEOPTIONS}
 fi