D3 beta tutorial

I’m having problems with the d3 beta tutorial (challenges). The code I type in works fine locally (using d3.js from d3js.org), but does not pass the online tutorial tests. Where is the proper place to post this problem? The viz gitter site does not seem useful. Probably the posted problem should get to the developer.

Thank you for helping with our beta testing efforts. All bugs are submitted and tracked using GitHub issues.