diff --git a/openmptcprouter/files/etc/init.d/openmptcprouter-vps b/openmptcprouter/files/etc/init.d/openmptcprouter-vps
index 06a0354d9..4d818b98e 100755
--- a/openmptcprouter/files/etc/init.d/openmptcprouter-vps
+++ b/openmptcprouter/files/etc/init.d/openmptcprouter-vps
@@ -229,7 +229,7 @@ _set_config_from_vps() {
 	[ -z "$shadowsocks_disabled" ] && shadowsocks_disabled=0
 	ss_key="$(echo "$vps_config" | jsonfilter -q -e '@.shadowsocks.key')"
 	ss_key="$(echo $ss_key | sed 's/-/+/g; s/_/\//g;')"
-	if [ "$ss_key" != "$(uci -q get shadowsocks-libev.sss0.key)" ]; then
+	if [ -n "$ss_key" ] && [ "$ss_key" != "$(uci -q get shadowsocks-libev.sss0.key)" ]; then
 		ss_method="$(echo "$vps_config" | jsonfilter -q -e '@.shadowsocks.method')"
 		ss_port="$(echo "$vps_config" | jsonfilter -q -e '@.shadowsocks.port')"
 		[ -z "$ss_port" ] && ss_port=65101
@@ -248,7 +248,7 @@ _set_config_from_vps() {
 
 	# Glorytun settings
 	glorytun_key="$(echo "$vps_config" | jsonfilter -q -e '@.glorytun.key')"
-	if [ "$glorytun_key" != "$(uci -q get glorytun.vpn.key)" ]; then
+	if [ -n "$glorytun_key" ] && [ "$glorytun_key" != "$(uci -q get glorytun.vpn.key)" ]; then
 		vpn="$(uci -q get openmptcprouter.settings.vpn)"
 		glorytun_state=0
 		if [ "$vpn" = "glorytun_tcp" ]; then
@@ -284,7 +284,7 @@ _set_config_from_vps() {
 
 	# MLVPN settings
 	mlvpn_key="$(echo "$vps_config" | jsonfilter -q -e '@.mlvpn.key')"
-	if [ "$mlvpn_key" != "$(uci -q get mlvpn.general.password)" ]; then
+	if [ -n "$mlvpn_key" ] && [ "$mlvpn_key" != "$(uci -q get mlvpn.general.password)" ]; then
 		uci -q batch <<-EOF >/dev/null
 			set mlvpn.general.password=$mlvpn_key
 			commit mlvpn