Embedded Google Calendar Permission Error - ICAL feed

Embedded Google Calendar Permission Error - ICAL feed

I made a change to one of the ICAL feeds on my Google calendar that is embedded in an Zoho Creator HTML view and now I am getting a permissions error ("Events from one or more calendars could not be shown here because you do not have the permission to view them.") when I try to view the calendar in Zoho Creator (without being logged into the Google account that owns the calendar)

I have re-added the calendar feed MULTIPLE times with the Public setting (altough I think that the first time I added it I may have forgotten to do this).

Is there any way to resolve this?