The first day of the term always sees a bit of a technical hiccup. It's because there's tens of thousands of people trying to register at once and mentors are working to set up your degree plan.

It sucks, yes. But by noon-ish EST it should be fine (or earlier) and then you should rarely, if ever, see issues throughout your term. It's just the first day that's a bit of a hiccup.

ETA: It's still down as of 2:21pm EST. Honestly this is the worse I've seen it and it seems to be a more widespread issue. I heard from my mentor within the last hour that indicated it would be "several more hours."

ETA, UPDATE: I was able to gain access and register for my courses at approximately 6:30pm EST this evening. Others are reporting similar so it looks like this is fixed or at least getting better.