FTS & dinamic DNS

[Desartstudio]

Hi i have a trouble , i have installed the FTS in my raspberry at home, i have put the raspberry in dmz, with ip 192.168.1.3, if i configure fts with this ip work fine if i call the local address, but i call my dinamic dns like example.ddns.net:5000 the page not work fine, but is not possible for me set the server with name but only for ip
Someone have a solution for this trouble?

this is if i call from ddns.net address