Is it repeatable? I have seen some timeouts, but our timeout setting is about 30seconds, which is massive. It could be that servers are busy at that moment. Or something else. 

I also noticed that some servers block free users after too many requests. In those cases, it comes back in the next day or so.  

 Hmm not sure it's repeatable. Seems to just come up once in a while, but can come up several times a day, sometimes not for a couple of days. Clearing cache seems to work.

But yeah I only know that cos someone told me that was a fix.