Cowboy is the name of an Erlang web server and Heroku uses Erlang for their routing. I imagine the reason Cowboy is showing up is due to Heroku's routing layer.
I would agree, but the fact that it suddenly stopped working points to carrier interference rather than Heroku (because as a developer focussed company, they would have informed OPs company of the change)
Heroku isn't in a frozen state. I'm sure that they change the code daily. The fact that it suddently stopped working doesn't really point to any specific endpoint unless you know which ones have changed. Then it might mean something.
