We're moving Fuelly.com to new servers this morning and there could be some bumps in the road. We're planning for a smooth move with minimal downtime, but there are often unplanned problems with a big move like this.
Please post here if you're having trouble with the site. You'll know you're at the new server if you see an asterisk in the footer of any page. Thanks for your patience. We're making this move to make things faster and more stable.
The technical reason for this problem is that IE8 and below on XP do not support Server Name Indication for secure connections. We're talking about potential solutions, but nothing will be a quick fix.
In the meantime, if you want to use Fuelly without certificate errors you can disable domain mismatch errors. You get there through Tools » Internet Options » Advanced » Security heading. And then uncheck "Warn about certificate address mismatch". Restart IE.
That will stop the errors, but it also makes your browsing slightly less secure. You have to take our word that we have the proper certificates, and you shouldn't have to do that. So we'll get this sorted out but there isn't a quick way to solve it.
For the time being we're not going to serve secure pages to IE on Windows XP. We don't have a way to fix this problem on our end without downgrading to a less secure certificate, which we don't want to do at this time. We're exploring some other options, but in the meantime just be aware that if you're using IE on XP you won't bet getting SSL pages for logging in or adding fuel-ups.
If possible, I'd recommending switching over to a newer version of Firefox on XP.