Rails Error: Missing template in view path app/views

My requirement is to render, according to response type

     format.attachment { render :template => ‘errors/permission_denied’, :status => 403 }

     format.html { render :template => ‘errors/permission_denied’, :status => 403 }

but I am getting error like

     “Missing template /errors/permission_denied.erb in view path app/views”

My response type for my request was "attachment"

then I have changed render code with full file name and it works

     format.attachment { render :template => ‘errors/permission_denied.html.erb’, :status => 403 }