iphone will not sync ical to mac

This worked for me.....

On the iPhone tap Settings > iCloud

Switch Calendars off then back on then restart the iPhone.

On the Mac open System Preferences > iCloud

Deselect the box next to Calendars then reselect it.

cannot sync till now... 😟

When I turn off the "calendars" button in Settings>iCloud, it asks what to do with the previously synced calendars...Keep on iPhone? or Delete? Which one do you do click?