Sharing icloud calendar with Cozi (free version)

While logged in from my PC desktop: I want to share my icloud calendar in Cozi with my partner (who uses Cozi). I selected calendar share in icloud, selected my own email (not icloud email) to share, got invite email popup with url and when tried to send got network permission error. What does that mean? How do I share my icloud calendar on Cozi? When I pasted url in cozi I got a pop-up that says can't complete and try again. I've tried many times. Thanks