I've been dealing with the same problem! I took me a while to work out it was due to being out of the US.
There is an easy and free fix I'm using. If you add the HOXX VPN Proxy extension to Firefox and hit the US server the log in seems to work fine. I don't know yet, because stupid AT&T won't give me an access code by email and the associated phone is in the US, for my elderly mother. Oh and of course the phone is broken. Fun times AT&T fun times.