I'm not gonna lie- this is a pretty noobish thing to do. I hadn't used AWS in a while, and I had forgotten that they only allow you to download the keyfile when creating the server instance. I had done this on the machine at my office, set up a bunch of stuff on the box, and left for the weekend. Then I allowed my home ip and tried to login, but I kept getting permission denied errors. Whoops! I was using the wrong keyfile. The problem then was that I didn't have the right keyfile!
I was able to get into the box by following the steps in this excellent video below. At a high level, these are the steps he goes through (I'll call the instance you are trying to access the primary instance and the one temporarily spin up the dummy instance.
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