Can you be more specific? That calendar at the present time should display one event: MLk day at best. Lesser holiday are not displayed (April Fools Day, the Ides of March, etc.) and the major holidays are too far out at the present time.

The upshot of all of this is that you need to ensure that the calendar you’re implementing actually has an upcoming event.

Edited to add: MLK day does not qualify as a US holiday, despite the schools and local governments having the day off. So it’s no surprise that feed doesn’t show any events: it doesn’t think there is anything for the next month.

This one might help. Try adding this to your calendar config: https://calendar.google.com/calendar/embed?src=ht3jlfaac5lfd6263ulfh4tql8%40group.calendar.google.com&ctz=America%2FNew_York