A 401 error isn't something that's likely to have happened by itself. It means you're not authorised, but usually you are by default. So that has been put up to block us out deliberately. So maybe the site was compromised, or some other catastrophe that's meant they've had to just put some blanket block on the public for a while.
I hope it comes back, it/was a very trustworthy source for all the basic info. Been stood in LFSs looking at a fish on LA loads of times.