How do I turn on Background App Refresh? It is light grey and won't slide to green.
I was trying to save battery life and turned off all Background App Refresh options by sliding the green button. Now, I can't use my workout apps with GPS. I went to settings>General>Background App Refresh, but it won't give me the option of sliding the main button to on. All apps appear light grey. What do I do now?
iPhone 5s, iOS 7.1.1