GCMPlayground doesn't seem to be talking to the server app

[ToddKerpelman]

So I can load up my GCMPlayground page at ipAddress:3000, and I can create a request just fine. However, when I attempt to submit the request, it doesn't seem to talk to the server. I see the pop-up saying "Sending message", but message doesn't actually get sent.

There's nothing wrong with the request itself -- if I cut-and-paste the data into a curl call, everything works just fine.

My Chrome console is full of errors like
(index):1 XMLHttpRequest cannot load http://xxx.xxx.xx.xxx:2376/socket.io/?EIO=3&transport=polling&t=1445463292227-174. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://xxx.xxx.xx.xxx:3000' is therefore not allowed access. I'm going to guess that's probably related?

[ToddKerpelman]

I'lll follow this up by saying it looks like this was user error. I was accidentally using the port of my Docker host (2376) when I should have been using the port of my server (4260, as noted in server.go)

I'll close this for now.