Error sound when I try to add key frame, when I ctrl/z , making animate completely unusable

I don't know what to do. Everytime I try to do anything in animate it just makes and error sound on my mac. I even opened one of the tutorials for animate to see if everything would work. The Gifs that normally show what to do aren't working, and ctrl-z isn't working either. My animate is up to date and now it is unusuable. Someone please help me!