Found the issue.
This is the script used for all ddns.
root@GL-MT6000:~# cat /etc/init.d/ddns
#!/bin/sh /etc/rc.common
set -x
START=95
STOP=10
PROG=/usr/lib/ddns/dynamic_dns_updater.sh
bypassvpn=`uci -q get vpnpolicy.global.service_policy`
if [ $bypassvpn = 1 ];then
PROG="sudo -g nonevpn /usr/lib/ddns/dynamic_dns_updater.sh"
else
PROG=/usr/lib/ddns/dynamic_dns_updater.sh
fi
boot() {
return 0
}
reload() {
$PROG -- reload
return 0
}
restart() {
$PROG -- stop
sleep 1 # give time to …
DDNS services in Luci don't run because uci -q get ddns.glddns.enabled returns nothing when using 3rd party DDNS providers or even when glddns is enabled.