Unable to configure Dyndns.it on FWA 710

Now That I moved the responsability of connecting from Fritzbox to Zyxel I wanted to move my dyndns.it host on zyxel but I'm not able.

The settings provided by the DNS platform (I don't know if it's the same as .com) are

Configurazione Modem

Service Provider:dyndns.it
dyndns custom
windtre ddnsHostname:advapiIT.homepc.it

Username:advapi

Password:[HIDDEN]

Parametri opzionali

Server:update.dyndns.itPath:/update URL:update.dyndns.it/?hostname=<domain>&myip=<ipaddr>

The result is

Why Current Dynamic IP is 0.0.0.0 and why Not Accepted?

Thanks