No 'access-control-allow-origin' Header - Same Domain?

Today I attempted to browse a new feature recently deployed to our testing environment (NOT LOCAL). After navigating to the new feature I was met with a blank page. Confused, I c

Solution 1:

The issue at hand was due to inconsistencies between environments.

In our production environment SSL is enforced with a redirect in IIS, while in our testing environment it is not. I was navigating to the site via a bookmark using http. Updating the bookmark, as @epascarello suggested, fixed the problem.