Vanguard: No Subscription Error

Just in from SOE, here is the reason why some users may be experiencing the No Subscription Error:

For a short time tonight, many people may attempt to log into Vanguard only to be told they do not have a subscription. You are getting this error because we are running a quick script to fix some issues. It is temporary, and you should be able to log in again in just a few minutes.

So, if you're experiencing this problem, just wait a bit and try again. However, if the problem isn't resolved then check out the Support Forums.