Zandronum

Grettings

I've compiled a 3.0 Zandronum server on my Raspberry Pi 3 and i've opened ports 10666 to 10700 on my router, then i run the server with the sv_updatemaster variable on true, but appears the following error after running the server "Can't find masterhostname master.zandronum.com! Either correct masterhostname or set sv_updatemaster to false". The server is shown on Doomsekker but only in local since in another network it doesnt apppear.

What could it be? Since the Raspberry Pi has a fresh Raspbian installation only i've installed the packages to compile the server, IDK if there's a firewall lik iptables to maybe block the server inside the RPi

Can you reach the master server from the pi with "master.zandronum.com"?

I'm trying to do a ping and i dont have answer, but on windows 10 if I do ping i've got the following ip "45.56.67.39" and doing ping with that IP on the RPi i've got response

EDIT: Fixed. It was a DNS problem, i've changed it to the Google DNS and after doing ping i've got response. Many thanks for your help!