Devise and OmniAuth Facebook CORS issue?

Hi there all,

I created this question on StackOverflow over the weekend because I was stuck, and I still am. I’m hoping someone can help point me at what I need to do to get the OAuth to Facebook to work as I remain at a loss to what I’m doing incorrectly.

The question is here outlining the CORS error I receive and what I’ve tried so far: ruby on rails - Devise-OmniAuth Facebook login stuck with CORS Issue - Stack Overflow

My reproduction GitHub (the exact code I’m using) is here: GitHub - firrae/devise-omniauth-facebook-CORS-error-example

I’ve gone over the documentation again and I’m mostly sure I’ve followed it to a T, but I’m not sure where the CORS issue is coming from, or how to solve it with the tools in Rails.

Any help or pointers in a direction are appreciated at this point.