Using Mac 10.8 Browserlab no longer can create previews. I've tried with Safari, Firefox and Chrome, all with no results.
The errors I get are:
Problem communicating with screenshot service, try later
problem communicating with server.
We've seen a few accounts get into a bad state where this happens continually for them. So far we haven't been able to identify the source of the problem though. Can you try again, make note of the time you see the message, and PM me with the date, time, timezone and the Adobe ID login you're using? We may be able to track it down further with that info.
Beyond that, do you have an alternate email address you can use to create a new account and sign in with to see if that clears things up for you for now?
1. logging out
2. logging in under a separate account (Browserlab worked)
3. logging out again
4. logging back in under the original account (which was broken)
Browserlab now works for me (although it seems a bit slower than usual)
I'm not sure how that could have fixed things but you might pass the info on to other people who are having the issue.
Let me know if I can pass along any additional info that might help others.