I can't select 'Optimize iPhone Storage'
I have this big problem with iCloud Photo Library. I have an iPhone 5c (8GB) and in order to save storage I'd like to turn on 'Optimize iPhone storage', but every time I select it, the check mark automatically switches back to 'Download and Keep Originals'. I can't even take pictures anymore... I just can't find any solution.
iPhone 5c, iOS 8.4.1