By default, the month to month navigation links on your calendar will not be shown if there are no additional events to display. This means the next and previous month links on the calendar will only display if there are events in the future or in the past to be displayed.
Calendar view with NO link for the next month, because there are no events in the future.
However, sometimes you may want to have these links on your calendar even if there are no additional events to view. To accomplish this, you'll need to add the following snippet of code to your child theme's functions.php file.
By adding the above code to your site, the Month View of your calendar will be able to move forward and backwards indefinitely from month to month even if there are no events to display.
Same calendar as above, with the added code. The next month link will now display even though there are no events to display.