So here’s a funny thing. I was looking at the Reddit thread that I looked at when I was setting this up the first time, and I found this:
Once you make any change to an access list, you need to go back to the proxy host that you applied that access list to and hit save again. Then give it a shot and see if it works.
And, uh…Yeah ¯\_(ツ)_/¯ it works now. Thanks for your time anyway!