Happened again today, at 06:00 GMT: on this occasion, it just took around 5 to 10 minutes to be accessible again. All the domain was unresponsive, not just the forum; other internet sites worked properly, and I tried on a different computer, with a different browser, where I had never logged into LuLa. Does not look like a DNS issue (browser stopped at "Waiting for...", instead of "Looking for..."), but I cannot say for sure, as I had limited tools on that computer.
Again, please do not take this as a complaint; I just thought you might want to know.