Hi… please note that due to caching within the plugin, updates to the calendar may take, by default, up to one hour to appear on your site. You can use the Clear Cached Calendar Data button on the ICS Calendar admin page to manually clear the cache or change the duration of the cache with the Transient (cache) expiration setting.
Also be aware that any other caching plugins may interfere with the calendar updates. If you are using a caching plugin, you may want to configure your calendar to load via AJAX.
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