Can you try adding
https://passport-oauth-martinmars.c9users.io to it (that’s what’s in the Site URL box at the bottom, which doesn’t actually need the
:8080 part since Cloud9 maps 8080 in your workspace to
:8080). It would be useful if you could post the URL that you’re getting the error on. I’m not experienced with Facebook OAuth, but I’ve seen some platforms that differentiate between
https in their app domains, so make sure those are the same.