When i try to log in, the login box is gone

also, when that bug didn't happened, i always saw  the error message saying that object doesn't supports  that method or property and it says lines:47 Char:9 URL:https://idp.nycenet.edu/isam/sps/auth? Plus, before the bug, I couldn't even join my own server. :(

Please help Minecraft is my only game to play <:(