Well..

https://solspace.com/docs/calendar/icalendar/


  All of the parameters listed in Calendar:Events are available for use here.


and then..

https://solspace.com/docs/calendar/events/#event_id

Have you tried hard coding a known (and open) event_id?

Solspace Calendar ICS for single event
I have made something wrong while creating some virtual hosts on Apache and now everytime I go to some_random_subdomain.mysite.com, if this subdomain does not exist or if it is not applied properly it redirects to a specific directory (which is assigned to a specific subdomain) and I don't know what do I have to do to stop it. Some help please.
