Errors without a reason (503 busy)

I see a lot of errors in my logs, comming from Anspress. Here is one from Google bot, that points to an old/test Anspress page. Now gives a 503, meaning some bug in your code causing the server to hang.

http://www.website.com/q-and-a/user/testuser/favorites/

Actually 404 errors within Anspress have a problem from what i see. Example

http://www.website.com/q-and-a/this-is-a-test-question-3/8032/ (works)

if a change that to anything else non existent, goes to empty page or a 503 (an error probably that doesn’t show).