Had the same issue a few times, the most recent one being just a few days ago. I tried disconnecting my VPN, it didn't work so I turned it back on. Other sites still worked fine. Then after lots of loops and waiting for around 10 minutes it solved itself.
Usually for me it just works after waiting for a long time, not sure if the causes for my issue are the same as Marcusta's though, since my internet is usually just really bad. Though even if my internet is bad it's still quite weird for it to take such a long time, and sometimes my internet wasn't even being that bad.
And this has happened to me before both on phone and on PC.