No, no clue.
Now that I'm back in the office, the same office as my coworkers, it's working as expected.
But that's actually horrible. It means we have a condition where requests work from one network, but not from another. (I'm fairly sure that the network I was on last week, at my in-laws's house, did not have a firewall. Even if it did, why would it block http requests?)
Obviously, I kinda need Munchkin to work from everywhere.