Yeah, I also could not login this morning to checkin for my flight. On Firefox Android, got an error after answering about 15 CAPTCHA, and pretty much the same thing on Firefox on my laptop.
Also, could not check in through the Android app because the app does not let me enter the date of birth of my girlfriend during the process, the buttons are there, but unclickable. it's been like that for weeks. The website never asks for the date of birth though (it's a domestic itinerary), just whether or not she is over 15