Cannot sync iCloud contacts - it just doesn't work
I have 3 Apple Laptops, an iPhone and an iPad.
Contact syncing works with 1 Laptop (MBP 2009) and all iOS devices.
Two Laptops (Retina MBP 2013, MacBook 2015 12-inch) cannot sync contacts (rest of iCloud syncs well). I have deactivated/reactivated syncing and even re-installed OS X on my MBP 2013 - without success.
All Laptops run the latest OS X version.
Any help much appreciated
MacBook (Retina, 12-inch, Early 2015), OS X Yosemite (10.10.4)