how to deauthorize all computers

I have my 6th apple computer. My last one died on me and I just got this new one. I deauthorized this computer. However, now when I try to authorize it, I get an error message saying that I have to deauthorize all my previous computers. I no longer have my previous computers and I am not prompted to anything that says "deauthorize all". The 3 options I get are "authorize this computer", "deauthorize this computer", and "deauthorize audible account". How can I deauthorize all computers so that I can get this new one to work? Thank you!