Error synchronizing Google Calendar with NC Calendar

I copied the link of my Google Calendar “secret address in iCal format” and pasted it into a new NC Calendar (read only), and I get an error, and it says it can’t create the calendar.

Has anyone been successful here?
Is there an option for true synchronization?
(Yes, I have installed the NC app “Google Synchronization.” (How do I configure it?)

I found all the answers here: