Yes. Whenever these outages happen, it always seems that it's their login system that is broken.

That implies that either the auth is too heavy (possible, ish) or their systems don't degrade gracefully enough and many different types of failures propagate up and out all the way to their outermost layer, ie. auth (more plausible).

Disclosure: I have scars from a distributed system where errors propagated outwards and took down auth...