Oh the joys of good service...
I sent customer care an e-mail querying the 499 status code and it's possible causes.
They called me back to tell me that they don't have error 499 defined, and that the
problem must be with my computer.
15 mins later, with no alterations to my computer at all, the server magically started
working again...
The joys of living in South Africa.
Sorry I couldn't find out any more... I'll see what other info I can get out of them on
Monday.