'Mobile viewport not set' even though I have included the meta tag

Question

I'm trying to build a responsive rails application. When I browser wank (manually adjust the browser), the application appears to be responsive. However, when I view the application from the browser console, it's not responsive.

When I run Google's Mobile friendly test, it reads "mobile viewport not set', even though i've included the following meta tag in the application.html.erb : <meta name="viewport" content="width=device-width, initial-scale=1.0">

I'm using

• Rails 3.2.17
• ruby 2.1.4p265 (2014-10-27 revision 48166) [x86_64-darwin14.0]
• Bootstrap (download from Bootstrapwebsite, not a gem)
• Heroku

How do i set the Mobile View Port?