Mac OS is not syncing with iCloud
I have several iOS devices that are syncing very well with iCloud. My Mac OS 10.13.3 suddenly stopped syncing. I have stopped and restarted Contacts sharing from System Preferences and rebooted several times with no effect. My iCloud is correct, iOS devices are synced & current but my iMac will not sync.
iMac, macOS High Sierra (10.13.3), late 2013, 3.2GHz intel Core i5