What am I missing about "https://api.flowdock.com/oauth/token"?

Discussion created by c.bartschat on Jun 19, 2017
Latest reply on Jun 20, 2017 by Conny Postma

I've been trying to get OAuth authentication working, but trying to exchange an authorization code for an access token is failing here. The post request's response is html, apparently of the Flowdock homepage. I'm quite baffled. This is a sample attempt on Postman.