Cannot save subscription http://localhost:3000/r/dfinity/rosetta-api

[will-yjn]

I successfully get the repo up and running. I can see all the feeds when I subscribe to dfinity/rosetta-api in the browser. It also says Subscribe to this feed: http://localhost:3000/dfinity/rosetta-api.atom or http://localhost:3000/r/dfinity/rosetta-api.

So I input and enter /feed subscribe http://localhost:3000/dfinity/rosetta-api.atom in the slack chat like I usually did, it returns Cannot save subscription(http://localhost:3000/r/dfinity/rosetta-api).

I also tried to subscribe to the link in the rss app in the slack app directory. It only returns Error fetching RSS feed. without more details.

Any ideas what I did wrong here?