Was finally able to login on my tablet but not with PC

For a week now i have been unable to log in to Citi Cards, trying 3 different PCs and 3 different browsers. I always get the "encountered a problem, trying to fix it" error. Support just gave me the usual "cache, browser settings" BS. I was able to finally log in using the Android mobile app on my tablet, which allowed me to take care of business but they really need to fix this mess.