NoMethodError in SettingController#region

undefined method `split' for nil:NilClass

Extracted source (around line #16):
14
15
16
17
18
19
          
def set_locale
locale = params[:locale] || session[:locale] || request.env['HTTP_ACCEPT_LANGUAGE'].split(",").first || I18n.default_locale
locale = :ja
I18n.locale = locale

Rails.root: /home/footbank/esi

Application Trace | Framework Trace | Full Trace
app/controllers/application_controller.rb:16:in `set_locale'

Request

Parameters:

None

Response

Headers:

None