Very odd server issue

I have a server running 2003 Standard R2. It also has the domain controller, AD, and DNS. I have roughly 30 computers in AD.

My problem:
We use a website, Skyrouter.com, to track our helicopters in while they are flying. This website uses Silverlight and it worked fine up until Tuesday. When you visit the site, everything loads, but it appears to not connect to the database which shows our tracking info. Here is the weird part. It works perfectly fine if you take the computer off the domain. You put it on the domain and it doesn't load the info.

I have not changed any settings within the past week on the server, router, etc. What could be causing the website to not load right only on domain computers?