Calendar does not show an event on multiple days. Only show it on the first day. For instance, I have a three-day vacation, I mark it starts one
first day and ends on the third day. The display of month only shows the event on the first day. It does not show the event on all three days.
Are there ways to fix this?

You marked it as a "whole day event" and set the end date 2 days later than than start date. Calender shows only the first day.

Of course the is: do not put start date and a different end date for the whole day event, but repeat the event twice.
Another way around would be not to mark it as a whole day event but insert start time and end time as well (but then the event is also shown during the day).
Hope this helps

Thank you. I'll give it a try.

The Month view only spans days when you make it an All-day event.

Thanks. That solved the problem.

No problem.