The remote host or network may be down. Please try the request again.
I can logon to the webserver from the internal network but when I try from the internet side I get the above error. www,xu1svr.org
First, welcome to IPFire
For the following I assume the url in question is a webservice you host on your internal system and behind ipfire. When I try to open the url it times out for me. DNS resolution works as I get a ip (1.128.111.216 atm). Check that the reported ip is the same as your external facing ip! If not then your dns entry needs work.
If the DNS is correct either there is/are an open port/s (80/443) but no service listening or ipfire is not responding with the icmp message while having the port closed. Any further ideas are just wild guesses now so I wait until you report back.
No, but it needs to apply the new rules. Should be a button at the top. That aside you will need rules to acces anything behind ipfire from the outside. The firewall blocks per default any (really any!) unsolicited attempt to connect to any port on RED. So you have to tell ipfire that it should forward requests on port 80 (http, not recommended!) and/or 443 (https) to your machine serving www.xu1svr.org.
This should only be relevant when the ip for your server changes so your ddns provider needs to update its dns record. Though it‘s an error you should fix.