icloud set up not working. Wheel just spins & spins

I'm trying to set up Icloud on my home IMac but the set up wheel just spins and spins for hours. 12 hours recently. Trying restarting the Mac and signing out then re-signing back in 5-10times with no luck. Anyone have any ideas ??? Also I presume Icloud works across all MacOS types.?? My work OS is High Sierra whereas my home Mac is El-capitan and I have to keep it like that for work/office software limitations....