The current vanity address you want returns
http://174.125.76.238:4040/ but there is no logon page available at that address. Either you own it and it's not online or someone else owns it and it also is currently not online.
If that is your external ip address, then you should be able to reclaim it. Historically the vanity address has been attached to your email address at the time of registration. Your license key is merely an MD5 hash of your email address. You can google any MD5 hash calculator to translate your email address into its hash return.
Since the new licensing scheme has been put in place there seems to be more issues relating to activating, reusing, and refreshing the registration process. Normally, if everything is set up properly you should only need to go to Settings/Network and Save whenever the external ip address changes, but recently it seems that problems are appearing more frequently here in the forum. There may be issues I'm not aware of under the new licensing setup.
I'm a legacy user, so I haven't had any issues. If you purchase a license and can't get it to work properly, you can always email Sindre and ask him to verify your registration information.