iCloud keychain won't work

When I singed in to my iCloud on my MacBook I chose all the things I wanted to synchronize to my other Apple devices, the keychain won't select and when I try to select it pops out other popups which all asked my iCloud password. When entered nothing happened. I tried to logout and log bag in but it still won't work. It works on my iPhone "iOS 9.3.2" but not on my Mac "OS X El Capitan 10.11.6". What can I do to fix this?